The plan was for Andrew Pinnock to replace Lorenzo Neal as the top fullback. But when his knee was slow to come around after microfracture surgery, that opened the door for undrafted rookie Michael Tolbert.
Tolbert proved he could handle the job, so Pinnock was let go.
The team also put two players on injured reserve after the final preseason game.
Scott Chandler, who had been seen an increase in snaps with Antonio Gates being down, injured his toe in San Francisco and is gone for the year.
Also landing on injured reserve was third-string center Cory Withrow -- he went down with a hamstring injury.
So tight end Kris Wilson, a recent cut from Philadelphia, was added to replace Chandler.
Kynan Forney, an offensive lineman, was added for depth. He was recently released by Atlanta; he had started 88 games for the Falcons in the last seven seasons.
The Chargers are also likely to start L.J. Shelton, and not Marcus McNeill, at left tackle. McNeill has been bothered for at least a month with a stinger in the shoulder area and has yet to be cleared to return to practice.
--QB Philip Rivers hardly skipped a practice during training camp, despite having the ACL in his knee repaired in the offseason. Rivers looked very good in his exhibition games and seems primed for another big year.
--RB LaDainian Tomlinson has the summer he and the team wanted -- he didn't play during the offseason games as coach Norv Turner didn't want to risk an injury. Tomlinson is in the prime of his career and seems bent on proving those people wrong who dumped on him for not returning to the AFC Championship Game when he sprained his knee.
--TE Antonio Gates (toe) is not 100 percent. But he still expects to play on Sunday and supply some kind of a threat. But Gates is not the Gates the Chargers have been accustomed to and his toe injury is something that is going to be monitored throughout the season.
--WR Chris Chambers has looked good in training camp as he forged an even stronger relationship with QB Philip Rivers than last year when Chambers came over in the middle of the season. With TE Antonio Gates hobbling, Chambers might see even more passes thrown his way.
--DT Jamal Williams has bad knees and is entering his 11th season. That said, he is good to go as the Chargers were very careful with him in the preseason. Williams is the key to stopping the run in the team's 3-4 alignment.
--DE Luis Castillo battled a balky back through most of the summer. But he declared himself ready to go and should be fine for the opener.
--ILB Stephen Cooper will miss the first of his four games after being suspended by the NFL for testing positive for a banned stimulant.
--ILB Derek Smith, will replace Stephen Cooper on running downs. Smith is a savvy pro and is rarely out of position. He's not the player Cooper is, but he won't be exposed too much.
--RB Darren Sproles will handle the kick- and punt-return duties. In addition, look for Sproles to get more looks in the base offense, sharing the backup role to RB LaDainian Tomlinson with Michael Tolbert. The coaches have gained much more confidence in Sproles playing in the offense.
--CB Antoine Cason, the team's top pick, has earned the nickel spot with his play during the preseason. That adds another impressive athlete to a cornerback unit that includes Antonio Cromartie.
The Chargers beefed up their roster in the offseason with three veterans who will start in place of…