Apologies for the delay on this one, I took the weekend off from the computer more or less and I didn't have a chance to work on this more yesterday. This was the hardest section so far to compile as offensive line men don't get any stats credited to them so it is harder to find out how much they played in any given year. Most of the info comes from short bio snippets on the team's official website but those were largely incomplete.
I've tried to group the players by specific position below, but you will note that some guys are listed as OT/OG etc, as the information I could find on them mostly indicated they were a back up who played both positions. I apologize for the inconclusiveness of the below information.
If desired I can post recruiting stars as well. From what I remember while compiling this list most of the guys who didn't end up as starters were lower rated players. In general there aren't a lot of 4 and 5 star offensive linemen to begin with (although certainly more than FB or TE).
2002 Winston Justice RT 6-7 297 4.9
2003 Sam Baker LT 6-5 305 5.2
2003 Travis Draper OT 6-4 270 4.79
2004 Taitusi Lutui OT 6-5 370 5.5
2004 Chilo Rachal OT/OG 6-6 310 4.9
2005 Charles Brown LT 6-6 249 5.12
2005 Thomas Herring OT/OG 6-6 320 4.8
2008 Matt Kalil OT 6-7 281 5.02
2008 Tyron Smith OT 6-5 260 5.1
2009 Kevin Graf OT 6-6 301 5.1
2002 Chris Doyle C/G 6-2 285 5
2003 Ryan Kalil C 6-4 255 4.9
2004 Travis Draper C/G 6-5 265
2007 Kristofer O'Dowd C 6-5 315
2009 John Martinez C 6-2 264 4.88
2002 Kyle Williams RG/RT 6-7 271 4.96
2003 John Drake RG/RT 6-4 360 5.2
2003 Drew Radovich LG 6-5 275 5.1
2004 Jeff Byers LG/C 6-4 280 4.8
2004 Thomas Herring OG/OT 6-6 292 4.8
2004 Alatini Malu OG 6-5 300 -
2005 Nick Howell OG 6-5 253 5.16
2006 Zack Heberer OG 6-4 269 5.2
2007 Martin Coleman OG 6-5 290 4.8
2008 Daniel Campbell OG 6-5 320 5.2
2008 Khaled Holmes OG 6-4 301 -
2008 Matt Meyer OG 6-7 290 5.19
2004 Round 2 #52 Jacob Rogers
2006 Round 2 #39 Winston Justice
2006 Round 2 #46 Deuce Lutui
2007 Round 2 #59 Ryan Kalil
2008 Round 1 #21 Sam Baker
2008 Round 2 #39 Chilo Rachal
2008 UFA Drew Radovich
2008 UFA Matt Spanos (now in CFL)
(Could be incomplete, this info is harder to find than I thought)
I wasn't able to find info about the 2001 line so I won't be able to contextualize as much but here are some highlights for most of the guys. Winston Justice started 12 games as a freshman, 10 as a sophomore, ran afoul of the law before his junior year and took a "redshirt" came back and started 12 more games as a senior. Sam Baker was recruited as a guard, switched to tackle and was a 3 time All American. Travis Draper failed to qualify the first time he was recruited, was recruited again a year later and signed as a guard, eventually moved to DL. Deuce Lutui was a JuCo transfer and later starter. Chilo Rachal was recruited as a tackle, shirted his freshman year, was a backup as a RS Freshman, a full time starter at guard and All Pac 10 second teamer as a RS Sophomore, got hurt as a RS Junior and decided to go pro early to help pay his families medical expenses. Charles Brown came in as a TE but got too big and moved to Tackle, he was all Pac 10 Honorable in 08 and I think you know the rest. None of the other guys under Tackle have had a major role yet.
I remember nothing about Chris Doyle. Ryan Kalil was a 3 year starter before moving on to the NFL. O'Dowd was his replacement in 2007 was something of a freshman sensation before getting hurt and missing a large part of the rest of the season. Made All Pac 10 in 08 and was the starter again this past season. John Martinez was listed as 4th on the depth chart at center this past year. Not on the list above is Matt Spanos who was an all Pac 10 Honorable Mention at Center, he was recruited as a defensive tackle.
We all know what happened to Kyle Williams after college. John Drake was a JuCo transfer who split time at RG and RT. Drew Radovich was a 2 year starter who made all Pac 10 honorable mention at one point. Jeff Byers was the Gatorade HS POTY as a Center (a rarity) and was moved to guard out of necessity as a freshman, started 4 games there before getting hurt. Missed the next two seasons with injuries and was granted a 6th year of eligibility this past season. Herring was another guy who missed the cut initially academically and was rerecruited the next year. Alatini "Tiny" Malu was another JuCo guy who was largely a career backup. Nick Howell and Zack Heberer both red shirted their first year, backed up two different positions their next two. Howell was a starter as a senior but Heberer was left as a back up due to Byer's 6th year of eligibility. Coleman, Campbell, Holmes and Meyer have all red shirted one year and been backups their other years. Meyer had surgery on his foot for the third time since HS.
It's hard to know what to make of the offensive line recruiting. USC has obviously had very good line play the last 7 years, and yet only Sam Baker and Ryan Kalil truly stood out at the college level. Not knowing a lot about the individual skillsets of the players also makes it hard to find any trends. As far as raw physical attributes go these guys seem to be all over the place in terms of size and speed, and I'm sure that a lot of them changed drastically when introduced to a real weight training regime and diet (have I mentioned how amazing the athletics cafeteria is on campus?). I don't really have any conclusions to draw I'm afraid.
How this applies to the draft/Current Roster
I think this quote might be of importance:
So, I spent the off-season working with the offense, and we recreated everything--philosophy-wise, rhythm, and principles--and the results have been phenomenal. Carroll turned to two professional coaches for assistance -- Alex Gibbs of the Denver Broncos and Jon Gruden, who was then at Oakland but moved to Tampa Bay. Denver had been known for possessing the best running attack in the NFL, and Gibbs was generally accorded most of the credit for developing it.
The whole article at the link is worth a read as it details the zone running schemes USC used since 2002. I believe someone asked in another thread if USC used Zone Blocking at all, so there's your answer. I have to admit I had forgotten about Coach Carroll contacting Gibbs for help. Actually reading that article again I have to wonder if that was what started the rift between Norm Chow and Pete, but I digress. I think the takeaway here is that the likely course of action would be for Coach Carroll and Coach Gibbs to try and find linemen who fit the Zone Blocking Scheme. Who that specifically is in this draft is something that I don't know much about.