The 49ers issued a press release announcing that Crabtree was placed on the physically unable to perform list, but they didn't say how long he'd be out. If Crabtree can't pass a physical before the beginning of the regular season in September, he must remain on the PUP list for six weeks.
Crabtree underwent surgery to correct a stress fracture in his left foot in 2009, and he's believed to have re-injured the foot June 6, the first day of player-run workouts. At the time, wide receiver Josh Morgan said Crabtree was sore because of new cleats he was wearing on the artificial surface at San Jose State.
Crabtree participated in the classroom portions of the 49ers' workouts, but he didn't attempt to practice after aggravating the foot issue.
The Bee reported that the 49ers are in the market for a veteran wide receiver because of Crabtree, and they had permission to speak with Chad Ochocinco, who was traded from the Cincinnati Bengals to the New England Patriots on Thursday. Comcast SportsNet Bay Area reported that the 49ersalso are talking with former San Diego Chargers wide receiver Malcom Floyd.
Crabtree missed his rookie preseason because of a lengthy contract dispute. He again missed the preseason in 2010 after suffering a neck injury during training camp.
Quarterback Alex Smith, a free agent who's expected to re-sign Friday, wouldn't be allowed to practice or participate in any physical activities with the team until the new league year begins Aug. 4. With running back Frank Gore yet to report for camp, that leaves the three most important pieces of the 49ers' offense off the field.
And perhaps nobody could use a full preseason more than Crabtree.
Missing training camp in 2009 slowed his rookie transition, and last season, the timing between Crabtree and Smith was off early. Crabtree rallied strong to finish with 741 receiving yards and six touchdowns, but the 49ers went 6-10 and missed the playoffs for the eighth consecutive year.
In addition to the foot issue this year, Crabtree also openly challenged Smith's status as the starter when he arrived and downplayed the quarterback's efforts to organize offseason workouts.
Crabtree, the 10th overall pick in the 2009 draft, held out of his rookie training camp while waiting to approve his contract. After a 71-day stalemate between him and the team, Crabtree agreed to a six-year deal with $17 million guaranteed.
The Associated Press contributed to this report.