Q: Who do you expect to fill the void at wide receiver?

HARBAUGH: “We’ll put (A.J.) Jenkins, (Quinton) Patton and Ricardo Lockette at the same position and let them compete and emerge. And the good news is somebody will emerge because they have to. And then the other side – Anquan Boldin, Chad Hall, Marlon Moore has been doing some real nice things in the offseason. Joe Hastings. Kyle Williams eventually will come back from his injury. He’s doing real well, coming along very nicely. Mario Manningham, probably a little later than Kyle, but he’s on track to be healed up and ready to go as well. A real good chance for some young guys to emerge, get the reps and contribute. I very much anticipate that that will happen.”

Harbaugh seems to be suggesting Boldin will take Crabtree’s spot at flanker. If that’s the case, who do you think will become the starting split end – Jenkins, Patton, Lockette or Williams? Or do you think Manningham will reclaim that job at some point this season?

To inform the debate, let’s look closely at Crabtree’s 2012 stats.

Michael Crabtree

Catches: 85 (tied for 13^th best in the NFL)

Yards: 1,105 (14^th)

Touchdowns: 9 (tied for 11^th)

Deep catches (passes traveling more than 20 yards past the line of scrimmage): 5 (tied for 42^nd)

First downs: 57 (13^th)

Third down conversions: 22 (5^th)

Third down conversions on third-and-more-than-seven-yards: 11 (2^nd, Reggie Wayne was No.1 with 12 third-and-long conversions)

YAC (yards after the catch): 543 (4^th)

YAC/reception: 6.4 (12^th, Percy Harvin was No.1 with 8.7 YAC)

Notice Crabtree was one of the best receivers running after the catch, and arguably the best receiver in the entire league on third down.

Now, let’s compare his numbers to the 49ers’ other receivers’ 2012 stats:

Anquan Boldin

Catches: 65

Yards: 921

TDs: 4

Deep catches: 10

First downs: 45

Third down conversions: 16

Third-and-long conversions: 8

YAC: 276

YAC/reception: 4.2

Vernon Davis

Catches: 41

Yards: 548

TDs: 5

Deep catches: 6

First downs: 26

Third down conversions: 4

Third-and-long conversions: 1

YAC: 164

YAC/reception: 4.0

Mario Manningham

Catches: 42

Yards: 449

TDs: 1

Deep catches: 3

First downs: 21

Third down conversions: 2

Third-and-long conversions: 1

YAC: 187

YAC/reception: 4.5

Kyle Williams

Catches: 14

Yards: 212

TDs: 1

Deep catches: 2

First downs: 10

Third down conversions: 3

Third-and-long conversions: 0

YAC: 76 yards

YAC/reception: 5.4

Delanie Walker

Catches: 21

Yards: 344

Touchdowns: 3

Deep catches: 8 (Best among tight ends)

First downs: 14

Third down conversions: 3

Third-and-long conversions: 1

YAC: 60

YAC/reception: 2.9

Randy Moss

Catches: 28

Yards: 434

TDs: 3

Deep catches: 3

First downs: 22

Third down conversions: 4

Third-and-long conversions: 1

YAC: 82

YAC/reception: 2.9

In addition to Crabtree, the 49ers will not have Walker or Moss this season, and who knows when Manningham will return from his knee injury. Those four players combined last season for 176 catches, 2332 receiving yards, 16 TD catches; 872 YAC, 19 deep catches; 114 first down catches, 31 third down conversions and 14 third-and-long conversions.

Do you think the 49ers can make up all of that production this upcoming season? If so, how?

Here’s another question for you: How good do you think the 49ers will be on third down this season without Crabtree? The 49ers converted 36.62 percent of their third downs last season, which ranked 22^nd in the NFL. Keep in mind, in 2011 – before Crabtree emerged as a dominant third down receiver – the 49ers converted 28.11 percent of their third downs, which ranked 31st.

Anquan Boldin was a good third down receiver for the Ravens last year. Who else on the 49ers do you think could emerge as a solid third down target for Colin Kaepernick?

Final question: Which 49er can replace Crabtree’s YAC? Kyle Williams? Vance McDonald? Neither Anquan Boldin nor Vernon David is a big YAC threat.

Double Bonus question: Delanie Walker was the most productive deep-threat tight end in the NFL last season. The 49ers always had two deep-threats on the field with him and Vernon Davis. Who will be the 49ers’ second deep-threat this season? Kyle Williams? Quinton Patton? A.J. Jenkins? Ricardo Lockette?

THE GOOD

1. Craig Dahl – He was the starting free safety, and he had the best day of all of the 49ers’ defensive backs. Dahl almost picked off Colin Kaepernick twice. First, Kaepernick tried to fire a pass to Chad Hall in the end zone in a 7-on-7 drill. Hall was running straight down the middle of the field, Dahl read Kaepernick’s eyes and undercut the pass. Dahl had it in his hands but he bobbled it and it fell to the ground. Later, in an 11-on-11 drill, Kaepernick tried to hit Vernon Davis downfield, but Dahl read the play all the way and easily knocked the pass away. Again, he had the ball in his hands but he couldn’t hold onto it.

2. Chad Hall – He was targeted five times, more than any other offensive player (Vernon Davis had four targets, Quinton Patton and Ricardo Lockette had three targets each and A.J. Jenkins had two targets). Hall made the only touchdown catch of the day – a 20-yard catch in the back-right corner of the end zone. McCoy threw the pass, and Hall beat Chris Culliver on the play.

3. Lawrence Okoye – He played Justin Smith’s position in 11-on-11 drills. That’s right defensive end, or the “under tackle,” to be more accurate. Okoye filled his gap well in run defense, and toward the end of practice he stuck his hand up and swatted away one of Kaepernick’s passes at the line of scrimmage.

4. Vance McDonald – He had a quiet practice – he didn’t get targeted until almost the very end of the afternoon, when he ran a deep route over the middle and Scott Tolzien threw it up high where only McDonald could catch it. McDonald reached up and easily plucked it out of the air with his long arms and big hands. He makes tough catches look routine.

5. Andy Lee – During the special teams portion of practice, Lee was on fire. He was blasting punts through the wind and consistently landing the punts next to the sideline.

THE NOT-SO-GOOD

1. Chris Culliver – He gave up the only TD of the day – a 20-yard catch to Chad Hall. Hall ran straight to the back corner of the end zone and McCoy threw it up for him. Culliver had good coverage, but he couldn’t locate the ball when it was in the air, so he never made a play to knock the pass away. Hall easily made the TD catch. Culliver struggled locating deep passes last season, too. He needs to improve this part of his game if he wants to take Carlos Rogers’ starting job.

NO SHOWS

Anquan Boldin, Tarell Brown, Darcel McBath, NaVorro Bowman, Jonathan Goodwin, Joe Staley, Mario Manningham.

PRESENT, BUT NO PARTICIPATION

Mike Iupati, Justin Smith, Aldon Smith, Ahmad Brooks, Tank Carradine, Quinton Dial, Nick Moody, Luke Marquardt.

PARTIAL PARTICIPATION

Frank Gore, Kendall Hunter, Kyle Williams.

EXTRA NOTES

1. Goodwin was absent, so Daniel Kilgore was the starting center. Adam Snyder filled in for Mike Iupati at starting left guard, and Kenny Wiggins filled in for Joe Staley at starting left tackle. Joe Looney was the second-string right guard.

2. Carlos Rogers was the starting left cornerback, and Nnamdi Asomugha filled in for Tarell Brown at starting right cornerback. The DBs who covered the slot were Rogers, Perrish Cox and Michael Thomas.

3. A.J. Jenkins, Quinton Patton and Ricardo Lockette each got reps at both flanker and split end, but none of them got reps in the slot. Chad Hall and Chuck Jacobs were the slot receivers.

4. LaMichael James and Chad Hall were the punt returners, and both guys did a good job fighting the wind and catching the ball.

1. Are the 49ers deep enough at wide receiver without Crabtree?

2. Who will step up while Crabtree’s out?

3. Will the 49ers sign or trade for another wide receiver?

4. Does Crabtree’s injury affect the 49ers’ Super Bowl chances? What about their playoffs chances?

5. Are the 49ers still the favorite to win the NFC West?

Q: Does it feel different from last year?

LOCKETTE: No, it’s still competition, but the job that we’re competing for happens to be one of the most important jobs on this team, and that’s replacing the best receiver on the team. We’re not taking this lightly, replacing our teammate who is definitely in our prayers. Hopefully we can replace Crab and hold it down until he gets back.

Q: How was it working with Kaepernick the past few months?

LOCKETTE: Oh man. The way he explains things and breaks things down, it’s made me a different receiver. Night and day. Just learning the playbook from someone you can totally relate to. He understands how I think and I understand how he thinks.

Q: How tough is it to replace Crabtree?

LOCKETTE: Crabtree was an all-around receiver. Coming into that spot, you’ve got to be able to block, you’ve got to be able to run excellent routes, you’ve got to be able to sometimes be a decoy because a lot of times he was double covered.

Q: Are you more of an X receiver, or can you play anywhere?

LOCKETTE: I’m more of an outside receiver. X or Z.

Q: What did Sonny Dykes say to you today?

PATTON: He told me it looked like I had a good practice, and he asked me how it was going up against Nnamdi Asomugha?

Q: What did you tell him?

PATTON: I told him he’s very long and very quick still.

Q: How does the news of Michael Crabtree going down affect you?

PATTON: Since Day 1, I’ve just wanted to come in and work. To lose a guy like Crabtree, I look to him as a big brother even though I haven’t been here long. It’s going to be hard, but we have no choice but to step up.

Q: Have you talked much with Crabtree?

PATTON: Yeah, he’ll tell us how to run the routes. He mentors us.

Q: Have you gotten your head around this playbook yet?

PATTON: I’ve been trying. Every time I try to learn a couple of plays, they put some more plays on me. I’m trying.

Q: Is that going to be the hardest thing for you this year, learning the playbook?

PATTON: Yes. That’s probably going to be the hardest thing.

Q: What about catching passes from Kaepernick?

PATTON: He throws pretty hard. You’ve just got to get your hands up.

Q: Have you ever seen anyone throw harder than him?

PATTON: No, sir. Never.

Q: How big a blow is it to the team to lose Michael Crabtree?

KAEPERNICK: Obviously, he’s a great player. He’s done a lot for this team. We just have to have someone step up.

Q: Have you talked with him? How’s he feeling?

KAEPERNICK: Obviously, he’s not happy about it. He’s just trying to get healthy now.

Q: Harbaugh says he doesn’t anticipate the injury will be season-ending. Does that bring some optimism to you?

KAEPERNICK: Yeah. Crab’s going to work. He’s going to be back.

Q: What was the mood on the field when he got hurt?

KAEPERNICK: It’s an injury. Nobody wants that to happen no matter who it is.

Q: Do you think Jenkins and Lockette can pick up the slack?

KAEPERNICK: They’re great players. They’ve been working hard.

Q: Are you confident there’s an adequate replacement who’s already on the roster?

KAEPERNICK: Yeah, we have a lot of talent out here. We have a lot of great players.

Q: What did Crabtree do so well?

KAEPERNICK: He got open. That’s what you want from a receiver.

Q: How many days have you been able to work with Boldin this offseason?

KAEPERNICK: I don’t know how many days. We’ve been getting good work in when he’s been out here.

Q: Do you mind sharing some of things you and Michael did together when you socialized?

KAEPERNICK: I’m here to talk about football.

HARBAUGH: Michael Crabtree underwent surgery to repair his Achilles tendon that he tore yesterday. The surgery was successful and we do not anticipate that it will be season-ending.

Q: Was it a partial tear or a full tare?

HARBAUGH: It was completely torn and completely repaired.

Q: How did it happen?

HARBAUGH: He was coming in motion, planted and started a route and he said it felt like someone kicked him in the Achilles – that’s what most people say that feels like. Good news is he woke up from the surgery and the first thing he asked the doctor how it went. He talked about the success of the surgery and he didn’t anticipate he’d be out for the year. His comment to that was, ‘Got no choice but to be back.’ Every day now is a healing day, and that starts today.

Q: How disappointed was he?

HARBAUGH: It’s a setback, but Michael’s young, he’s strong. Everything will be a positive approach to healing and we’ll anticipate great things. Another thing right now is if you look at the young receivers on our team that will emerge because they have to emerge. I’m excited to watch them compete for that spot.

Q: Is this the exact same injury Kendall Hunter sustained last season?

HARBAUGH: Same injury, yes.

Q: So is Crabtree on a similar timetable as what Hunter was on?

HARBAUGH: There was a different process with Kendall because there was more time. They took more time after the injury to do the surgery. A bit of a different approach the way I understand it, talking to doctors.

Q: Are you considering bringing Randy Moss back?

HARBAUGH: We’re excited for the young receivers that we have, and feel that somebody’s going to emerge there because they have to. Competition will create that, and we’ll look forward to watching that.

Q: Are you pleased Jenkins and Lockette spent the offseason training with Kaepernick?

HARBAUGH: Yeah, the guys they are, the players that they are, and the opportunity that they have, all those things will facilitate their emergence.

Q: Why wasn’t Anquan Boldin here today?

HARBAUGH: He had some prior commitments. For this week.

Q: Anybody standout this week?

HARBAUGH: Oh, yeah, there’s a lot of guys standing out. Right now, we got a long way to go, a long road to hoe. We understand that, and our guys are working on getting better every single day, coming out here with a plan what they need to get done before the day is over and their head can hit the pillow and they can feel good about what they accomplished. I like the way our team is working. I like the way they’re going about their business. It’s serious, and they’re focused on improving.

Q: Was Crabtree doing 11-on-11 drills when he tore his Achilles?

HARBAUGH: 7-on-7.

Q: How did Kaepernick play this week?

HARBAUGH: Kap was sharp again today. He’s been really strong, running the offense, throwing the ball extremely well, he’s in great physical shape. He’s in total command of the offense.

Q: How did McCoy play this week?

HARBAUGH:  He had a good day today. Colt was very sharp, as well. He had probably his best day. Like every other team right now, they’re building the knowledge for the system, getting better and better at it each day. That’s job No. 1. The second thing is, maybe, building that callous for playing football. So far, so good. It’s going well.

Look for Anquan Boldin to be the 49ers’ starting flanker as long as Crabtree is out. As far as split end goes, that spot probably is wide open.

Q: What’s the mood like on the team right now?

ROGERS: It’s always every team’s goal to win the Super Bowl. This is where it starts. Preparing, getting stronger, learning the offense, defense and special teams.

Q: What kind of role do you think Nnamdi Asomugha will have this year?

ROGERS: I don’t know. He’s going to have a big role. They brought him in for a reason. There’s going to be competition at the corner spot. They didn’t bring him in to sit on the bench.

Q: You’ve been a starter here and a starter throughout your career, but do you go into this offseason like you’re competing for your job?

ROGERS: I don’t know. I’m told I’m the starter, but any day someone could take your job. That’s what people are here for, to compete. People behind me are trying to take my job and move up. I don’t take it lightly and I don’t take anything for granted. I just continue to work.

Q: When you say you’re told you’re the starter, you’re told by whom?

ROGERS: They put out a starting list. There’s a starting 11 out there. I feel I’m the left corner on this team, and I’m going to continue to perform and play like I’m the left corner on this team, a starter on this team. Patrick Willis is out there at the Mike. He’s not told that he’s the starter, but is someone going to take his job? No. He’s a starter on this team and he’s going to go out there and work each and every day as if he is.

Q: You talked about playing left cornerback. Do you think you’ll be covering the slot in the sub packages like you have in the past?

ROGERS: Yeah, in sub packages.