SANTA CLARA -- The decision to activate wide receiver Michael Crabtree will come in the next 48 hours, 49ers coach Jim Harbaugh said Saturday.

The 49ers have to make a decision on activating Crabtree by Tuesday, and it remains unlikely that he'll play in Monday night's game against Washington. But Harbaugh wasn't ready to declare him out -- or in.

"It's been good. Did some good things," Harbaugh said of Crabtree's week of practice.

Crabtree began practicing Nov. 5, thus triggering the three-week evaluation window. The 49ers must activate him from the physically-unable-to-perform list by Tuesday or place him on injured reserve, ending his season.

They also could activate him to the 53-man roster but still keep him inactive on game days until he is ready. He's recovering from a torn right Achilles suffered May 21.

The 49ers' leading wide receiver from last season wasn't seen on the practice field as the team stretched before Saturday's practice, the only portion that was open to the media.

He hasn't been seen participating in team drills in two weeks.

Wide receiver Mario Manningham (knee) was limited at practice again Saturday and is questionable for Monday's game. Last week he had one catch for 8 yards in limited playing time agaisnt New Orleans. Jon Baldwin would likely start with Anquan Boldin if Manningham can't play.

  • Cornerback Tramaine Brock spoke with the media for the first time since the team announced a four-year extension with the former undrafted free agent from Belhaven University (Miss.), a tiny NAIA school. The deal is worth $16 million, with $7 million guaranteed.

    Brock leads the 49ers with four interceptions and will start Monday in place of injured Tarell Brown after spending the first 10 games as the team's No. 3 cornerback.

    "It was just a mindset coming in," Brock said of earning the contract. "Undrafted, just working hard and keep focused and when it's my time to go out there and play, just execute and play to my ability and keep on going, and it led me to a four-year extension."

    Harbaugh referred to Brock as a tireless worker.

    "He's done an excellent job, very much a success story," Harbaugh said. "A small college guy that just works and works and works, and it pays off for him. He's been that in the offseason, he's been that way during the season, been very productive in games. Just happy for him."

  • Adam Snyder re-signed with the 49ers this offseason after spending one season in Arizona, knowing that he could be a flexible player capable of filling several spots on the offensive line.

    He'll get his first start this season Monday when he takes over at left guard for Mike Iupati, out with a knee injury. But his familiarity with the 49ers isn't the only reason he came back.

    "I like what they have going on here. I'm familiar with the guys on the coaching staff and the offense and the community. All those things played into my decision," Snyder said. "At the end of the day, I felt this was my best chance to win a championship. I still believe that. Everybody in this locker room believes that."

    Snyder tried to add some perspective to the 49ers' 6-4 record.

    "We look at it as it's adversity," Snyder said. "We've really only lost four games. We can finish 12-4, and nobody's even going to think about what happened in Week 8, 9 and 10."

  • Tight end Garrett Celek (hamstring) and defensive tackle Ray McDonald (ankle) are also questionable. Brown (ribs) and Iupati (knee) have been ruled out.

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    MONDAY'S GAME

    49ers (6-4) at Washington (3-7), 5:40 p.m. ESPN, KPIX