Offensive lineman Jon Jansen returned to Redskins Park this afternoon on crutches and wearing a cast after suffering a season-ending rupture of his left Achilles' tendon in Monday night's exhibition game.

Jansen, considered by some to be one of the premier right tackles in football, was hurt on Washington's second offensive series against the Denver Broncos in Canton, Ohio -- a game the Redskins won, 20-17 -- and said he will be off his left leg for at least the next three months but aims to get back for the start of minicamps in the spring. His loss is a significant blow to Washington and will cause the coaches to juggle an offensive line that struggled last season.

The return of Hall of Fame Coach Joe Gibbs and his renowned offensive coaching staff had energized Jansen, who was selected 37th overall out of Michigan in 1999 and is Washington's longest serving player, and he was optimistic that the offensive line would thrive under Gibbs and line guru Joe Bugel. With a lefty quarterback, Mark Brunell, vying for the starting job, Jansen's position on the right side of the line was even more important to the team's success. Jansen returned with the team from Ohio early this morning and said he slept very little with the injury weighing heavily on his mind.

"It's just been running through my head," Jansen said. "I think anybody will tell you who's had an Achilles injury, it's not a very painful injury, but for me the pain has never been really physical; it was really emotional for me. It's frustrating, because we tread water for three or four years and then things really start to look up and now you've got to watch it from the sidelines. That's the part that hurts the most."

Jansen said he felt his ankle buckle under in the first quarter Monday -- he is unsure of the synthetic field turf recently installed in Fawcett Stadium in Canton had anything to do with the freakish injury -- and quickly realized it was serious. Jansen could not get off the ground, needed assistance to the sidelines and was rushed to a bench. Ice was applied to his ankle and Jansen was clearly despondent, holding his head in his left hand while teammates and coaches tried to console him. A towel was then draped over his head and he was carted off the field for medical testing, which confirmed the rupture.

Jansen, 28, had never missed a game in his pro career, making 80 straight starts, and prided himself on his durability. It had become one of his hallmarks dating back to his college days and the Redskins were counting on a Pro Bowl type season from him.

"Immediately, it was just the thought that everybody I've known," Jansen said, "and everybody who knows me, they don't expect Jon Jansen to be laying on the ground and having to be helped off the field. At first you feel just like you let everybody down, but then you realize that there's really nothing you could have done about it. There was nothing I could do to prevent it, as it's been explained to me. It's unfortunate, and it's something I have to deal with and the Redskins have to deal with, and obviously we'll all deal with it together."

Jansen said he will switch his focus to helping his teammates, lending advice and taking part in meetings ("By no means is this year over for me in terms of being part of the team," Jansen said. "But it is in terms of being on the field.").

The Redskins could insert Kenyatta Jones, a three-year veteran who was signed in 2003 from New England, into Jansen's spot, or perhaps move Derrick Dockery, who came on strong in the second half of last season, to the right side and then tinker with the left side of the line. Rookie lineman Mark Wilson, a fifth-round pick, and three-year veteran Daryl Terrell could also see more playing time due to the injury, and the Redskins might also look to sign or trade for a veteran lineman, although the timing of Jansen's loss will make it difficult to acquire an impact player.

Jansen, meantime, will spend the next six weeks in a non-weight bearing cast and he hopes to be able to begin jogging three months from now. His size, 6 feet 6, 305 pounds, could push those projections back given the nature of this injury, but Jansen would like to be able to begin practicing in four months, allowing him to get into good shape for the start of off-season workouts.

"It's just a matter of how long it takes to get your strength back," Jansen said. "For a normal-sized individual, it's obviously less because you don't have as much weight to support. But I've always been a quick mender, I don't swell very much and there wasn't very much swelling in it today, so I'm shooting for the four-month mark . . . It's just a pain in the butt for a while and I'll be back next year."