Jon Jansen suffered a small fracture at the base of his thumb during Monday's practice at Redskins Park, the team has reported.
Team officials stressed that the injury is not serious and Jansen is still expected to start at right tackle in this Sunday's regular season opener against the Chicago Bears.
Jansen will be fitted with a splint and cast and will continue to take part in practices this week.
Despite the injury, Jansen stayed on the field through the end of Monday's two-hour practice. He even stopped to speak with reporters coming off the field, although he did not reveal the injury at that time.
Asked if the Redskins' offense had played together enough in the preseason to develop a rhythm, Jansen replied: "I think so. We didn't want to wait until after the first [regular-season] game and then have to somehow find our rhythm. We were able to find our rhythm in the third game of the preseason [against the Steelers]."
In that game, the Redskins' offense racked up 367 total yards and did not allow a sack to one of the NFL's top defenses from a year ago.
During training camp and preseason, the Redskins spent a lot of time focusing on improving a passing game that was ranked 31st overall last year. At times, training camp seemed like it was more of a passing camp.
Jansen said the focus was necessary so that Patrick Ramsey could get a feel for new receivers Santana Moss and David Patten and get comfortable behind an offensive line that includes Jansen again.
Jansen missed the entire 2004 season with an Achilles injury. This Sunday's season opener against the Bears will be his first regular-season game since Dec. 27, 2003.
"We have a greatly improved passing game and we have guys who can get downfield," Jansen said. "Our quarterbacks are confident that they're going to stay protected. That's the big difference. They're not going to be standing out there thinking about who's going to sack them. They're going to stand back there and wait for [receivers] to get open."
Jansen believes the current offensive line, with Randy Thomas, Casey Rabach, Derrick Dockery and Chris Samuels, may be the most talented group he's ever played with as a Redskin.
"We've had some good players in the past, but I think this is the best unit I've ever been a part of," Jansen said. "We haven't played a game yet, though, so let's see how we do."
