Shaw, who had major knee surgery after being injured midway through his senior season at Michigan State last year, likely will be placed on a PUP list that will make him inactive for the first six games of the season, then give him a three-week window after that in which the team can evaluate his progress and either activate him or place him on injured reserve for the rest of the season.
"We're going to have to play that one out," 49ers coach Steve Mariucci said Sunday evening. "We don't need to rush him. He's a rookie, and we signed Jim Flanigan as an inside tackle on defense. So we've got some depth there. So we're just going to proceed with caution with Josh because there is absolutely no reason to hurry him back."
Mariucci said that, after a late Sunday meeting involving coaches, scouts, trainers and other team personnel, the Niners may decide to place other players on an active PUP list, which would allow them to work out on the side with physical development coordinator Jerry Attaway without counting against the team's 80-man roster.
Safety John Keith, who is coming back from knee surgery and did not participate in any spring minicamps, is a prime candidate for such a move.
"We have to see where he is physically," Mariucci said. "He's been working out and he's been making progress. But we need to determine is he ready to go, is he A-OK."
Rookie cornerback Teddy Gaines (quadriceps), defensive tackle John Schlecht (back), cornerback Jason Webster (hamstring) and receiver Donnie O'Neal (foot) also are candidates to be held out of practice or placed on PUP when camp begins Monday.