Training camp has not yet begun, but already the Redskins have lost a player.

Offensive lineman Mike Williams is sidelined for the season after suffering a pulmonary embolism in early July.

"Mike will be out for the year," head coach Mike Shanahan said. "Mike had a blood clot in his calf. Then he took x-rays and it was in his lung. So they put him on some blood thinner. Mike cannot obviously play with blood thinner."

Shanahan called the injury a setback for both Williams and the Redskins.

"When something like that happens, you're just glad you caught it before it gets serious," Shanahan said. "It's something that doctors looked at right away. It's something they were very happy they caught early.

"He'll definitely be out this year, but maybe in six months he'll be reevaluated. If he has taken the proper amount of time to be away, he could possibly play in the future."

After a three-year absence from the NFL, Williams returned last year and started eight games at right tackle and right guard for the Redskins.

This season, Williams was expected to compete for a starting job at right guard.

Prior to the Redskins acquiring Jammal Brown on June 21, he was slotted to start at right guard, but Brown's presence allowed the team to move Artis Hicks to the position.

"Mike was the starting right guard for all of offseason, almost 1,200 plays," offensive line coach Chris Foerster said. "That's a lot of plays of off-season work. He did a nice job for us and we counted on him to start or be a reliable backup. Losing him is unfortunate. But it does create opportunities for other players."

Young linemen Kory Lichtensteiger, Chad Rinehart, Edwin Williams and rookie Erik Cook could be in the mix to back up at right guard.