Michael Crabtree will return to the gym this week. So says a Tweet the 49ers receiver sent out Sunday.

Of course, Crabtree's workout routine won't include him squatting 450 pounds or running gassers until he pukes. He'll be eased back into the weight room, probably starting off on a stationary bike or an elliptical machine to maintain his conditioning. That would fit the time line for recovering from an Achilles' heel tear. Crabtree had surgery to repair the tear on May 22. This week is about six weeks from that procedure.

I've spoken to several orthopedic surgeons about Achilles' tears, and every one of them said that six months is the absolute earliest Crabtree can expect to be back on the field. The 49ers, of course, have declined to discuss Crabtree's surgery and recovery, saying only that they expect him back this season. Here's Dr. Eric Giza's - he's the chief of the foot and ankle service at UC Davis - time line for getting an athlete like Crabtree back in playing condition:

* Two weeks after surgery: Patient is in a walking boot. Not long ago patients had to wear a plaster cast for six weeks after surgery. The boot, however, preserves feeling and range of motion in the ankle and leads to less atrophy of the calf muscle.
* Four to six weeks: Patient starts to put weight on the foot. For an elite athlete like Crabtree, this can start at four weeks and usually begins in a pool. At six- to eight weeks, patients might begin working on a stationary bike or an elliptical machine to maintain their fitness.