The Chargers declined to offer specifics of the surgery.
Hardwick, a six-year NFL veteran who was a Pro Bowler in 2006, was hurt during the Sept. 14 season opener at Oakland, sustaining what the Chargers said was a sprained ankle. He missed Sunday's 31-26 home loss to the Baltimore Ravens.
Eight other players, including running back LaDainian Tomlinson and rookie right guard Louis Vasquez, missed practice Wednesday. Coach Norv Turner hinted that Tomlinson (ankle) and Vasquez (knee) might miss their second consecutive game when the Chargers host the Miami Dolphins on Sunday.
Turner said the team will hold off deciding whether to put Hardwick on injured reserve -- and losing him for the rest of the season -- until they can gauge his recovery and if they need to use the roster spot for another player.
"We would love to not be in position where we need it," Turner said.
Fifth-year pro Scott Mruczkowski will continue to start at center. Normally a backup guard, Mruczkowski was moved to center in the spring.
"It's tough to lose him for any amount of time," Turner said of Hardwick. "We're fortunate to have Scott. We made that move in April. We're fortunate we made it back then so we're not trying to catch up even more than we are right now."
The Chargers last week signed Dennis Norman, who has played center and guard.
Chargers general manager A.J. Smith didn't return a call seeking comment.
As for Tomlinson and Vasquez, "It's not day-to-day right now," Turner said. "I'm not counting on them being able to practice tomorrow. If they can, it would be a bonus."
So that could put them in jeopardy of not playing Sunday?
"Yes it could," Turner said.
Others missing practice Wednesday, according to the team, were outside linebacker Shawne Merriman (groin), backup outside linebacker Antwan Applewhite (hamstring), backup defensive end Travis Johnson (groin) and guard Kris Dielman, left tackle Marcus McNeill and safety Eric Weddle with illness. Punter Mike Scifres was limited because of a groin injury.
"It's a tough day for us, from a standpoint when you know there's certain guys you're trying to get back, and I think those guys are making progress," Turner said. "None of them were in position to practice today."
Copyright 2009 by The Associated Press