Arthroscopic surgery yesterday revealed that quarterback Mark Rypien's left knee suffered more serious damage than was originally believed and that he's lost to the Washington Redskins for six to eight weeks.

Rypien sustained damage to two ligaments and had some stretching of the soft-tissue casing that houses the knee joint (the posterior capsule), Redskins team physician Charles Jackson said.

No repair work was performed during the one-hour procedure, and Jackson said the capsule and the ligaments -- which have partial tears -- should heal normally over the next few weeks.

Rypien and the Redskins had hoped for better news, although they suspected some damage had been done Sunday when guard Mark Schlereth rolled Dallas defensive tackle Dean Hamel into him.

"We're disappointed for Mark," Coach Joe Gibbs said. "The other guys are going to have to play harder. It's tough for him and it's tough to understand. It's particularly disappointing because our quarterbacks have probably been hit less than any in the NFL. We wind up getting a guy hurt and that hasn't been the case with others who've been hit more."

The Redskins will place Rypien on injured reserve today to make room for veteran Gary Hogeboom, who agreed to terms on Monday and was at Redskin Park yesterday for a morning skull session on the Washington offense.

Rypien won't be eligible to come off injured reserve for at least four weeks, and if his rehabilitation goes well, he'll miss about eight games. That means he could return around Thanksgiving.

The Redskins play at Dallas on Thanksgiving Day -- their 11th game of the season -- then have 10 days off before finishing with five games in December.

Hogeboom will serve as backup to Stan Humphries this week at Phoenix. Veteran Jeff Rutledge, on injured reserve, can return to practice next week.

Gibbs said no decision has been made on whether Rutledge will be added to the 47-man roster. It's likely he won't be since such a move would mean cutting another player. A more likely scenario would have Humphries and Hogeboom on the game-day rosters and Rutledge practicing during the week.

Teams that have three quarterbacks normally activate only two, and if needed the Redskins can have until 4 p.m. Saturday of each week to activate Rutledge.

"I don't know what I'm going to do about that," Gibbs said. "We've had two {quarterbacks} all the way, and I'm not committing to anything. We've got to cross that bridge when we come to it. We've got other problems back there right now trying to figure out who to do what with, who's inactive, that stuff."

Rypien spent last night at Arlington Hospital and will rest at home a few days before beginning a rehabilitation program at Redskin Park. Trainer Bubba Tyer said Rypien's rehab probably will begin late this week.

He said its early stages -- about the first 10 days -- will consist only of icing the knee, then applying electrical stimulation to reduce swelling.

After that, Rypien will do exercises designed to get back the full range of motion before getting into strengthening work. Tyer said Rypien should be walking with assistance in about three weeks, but wouldn't predict when he would be back on the practice field.

During yesterday's surgery, Jackson discovered that Sunday's collision tore Rypien's lateral collateral ligament and the anterior cruciate ligament. Rypien had surgery on his left leg while at Washington State University to repair the medial collateral ligament. Jackson also discovered some scar tissue around the cruciate ligament.

But none of that is expected to be a problem. Jackson said Rypien should have a complete recovery and that there's no reason to believe his career won't continue normally.

"It was more {damage} than we anticipated to the anterior cruciate ligament," Jackson said. "But the cartilage surface looked very good. There was some scarring from a previous surgery, but no chips."

Rypien still has "good stability" in the knee and "his mood was very upbeat," Jackson said.

Meanwhile, Hogeboom met with Redskins quarterbacks coach Rod Dowhower for two hours yesterday morning to go over the playbook, which is similar to the one former Redskins assistant Joe Bugel took to Phoenix when he became head coach.

Hogeboom started 13 games for the Cardinals last season and was cut late in training camp after Bugel gave the starting job to second-year man Timm Rosenbach.

"There's a few different things," Hogeboom said, "but as far as the basic offensive game plan and strategy, I'm very familiar with it and it won't take me long at all. I'll have most of it down tonight and tomorrow."

Hogeboom spent his first six seasons with the Dallas Cowboys in years when the Cowboys-Redskins rivalry was still among the best in football.

"Playing with the Cowboys, you got the feeling of adrenaline walking into" RFK Stadium, Hogeboom said. "It's good to be here with a class organization, because once you've been in the league 11 years you find out what the class organizations are and the ones that are a little different. Playing against opponents through the years, they have a feel of how you can play and what type of player you are and what type of person you are. I always liked playing against the Redskins, but I always had a lot respect for them."

When the Redskins get on the practice field today, Humphries will be taking snaps with the No. 1 offense for the first time since training camp. In fact, Humphries will be running Washington's plays for the first time since training camp.

It was somewhat lost in his five-of-13 performance during Sunday's 19-15 victory over Dallas, but with only two quarterbacks, Rypien took virtually all the snaps with the offense in practice.

Humphries got his work by running the opponents' offenses. He wouldn't use it as an alibi for what he called a "mediocre" performance, but said he would at least go into this week's game with a better feel for things.

"It's different when you're not getting the practice snaps you want," he said. "I'm still new to our offense and what we wanted to do, but it's not automatic like it might be if you were running the plays during the week yourself."

Arthroscopic surgery on QB Mark Rypien's left knee reveals damage to two ligaments and the soft-tissue casing that houses the knee joint. He will be put on injured reserve today and is expected to miss up to eight weeks.

Newly signed QB Gary Hogeboom -- the backup to Stan Humphries when the Redskins play at Phoenix Sunday night -- said he should have the team's basic offensive game plan learned by today.

Coach Joe Gibbs said no decision has been made on whether veteran QB Jeff Rutledge will be added to the roster when he is eligible to come off injured reserve next week.