The San Francisco 49ers returned to the practice field Wednesday afternoon, and they were without two starters. WR Michael Crabtree and OT Anthony Davis both were listed as not participating. According to the beat writers, Crabtree and Davis were both working out separately in the weight room. Marcus Martin was also listed as a DNP, but his dislocated knee cap made this an expected absence.

Crabtree was dealing with a reported hamstring injury earlier in camp, so it is possible this is connected to that. There are still two more days of practice, so we can't really take a lot from this. If Crabtree gets in a practice session by Friday, he should play. And given that this is his first game in his home town, even no practice might not be enough to keep him off the field.

Anthony Davis missed all of the offseason workout program, training camp, and the preseason while dealing recovering from shoulder surgery. He suffered the injury early in the 2013 season and played through it before having surgery earlier this offseason. He said he expected to be back by Week 1, but given his absence to date, I'd say his chances of playing on Sunday are less than those of Crabtree. That is based on my limited knowledge of each of their injuries, so take that into consideration. If Davis does not play, Jonathan Martin would get the start in his place at right tackle. He struggled early in the preseason, but appeared to improve as it wore on. That might have something to do with getting back to 100 percent from his summer bout with mono.

Here are the full practice reports:

49ers

Did Not Participate: WR Michael Crabtree (calf), T Anthony Davis (hamstring), C Marcus Martin (knee)

Cowboys

Did Not Participate: DE Anthony Spencer (knee), T Darrion Weems (shoulder)

Limited Participation: DT Terrell McClain (ankle), DE George Selvie (shoulder)

Full Participant: QB Tony Romo (back)