49ers face logjam on injured reserve with Demarcus Robinson out 3-6 weeks

The San Francisco 49ers look like a legitimate contender through two weeks. At the same time, the team already has so many injuries that it is considering keeping players with multi-week ailments on the active roster, rather than placing them on the injured reserve list.

NFL teams can place an unlimited number of players on IR during a given season. Players must miss a minimum of four games once put on IR. But only eight of them can be designated to return. Thus, as wide receiver Demarcus Robinson and defensive tackle James Thompson Jr. grapple with high ankle sprains that could keep them on the shelf for 3-6 weeks, according to head coach Kyle Shanahan, the 49ers may hold both players on the active roster so as to not cut into those eight spots.

"Those guys (Robinson and Thompson) are right in that area … of how long those take (to recover from)," Shanahan said. "(But) it's real early for us to have as many (injuries) as we've had, so we got to balance all that out."

Robinson caught three passes for 34 yards before he was carted to the locker room early in the 49ers' 35-13 shellacking of the Miami Dolphins on Sunday at Levi's Stadium. Robinson had worked his way into the No. 3 receiver role for San Francisco following injuries to Ricky Pearsall and De'Zhaun Stribling .

"Yeah, it sucks," quarterback Brock Purdy said postgame of Robinson's injury. "These are all extremely great playmakers that, looking at our roster in OTAs and camp, it's like, 'Oh shoot, we can do some damage.' And then Ricky goes down, Stribling, and now D-Rob. … for them to go down early in the season like that is tough."

In the meantime, Shanahan said fellow wide receivers Jacob Cowing , Jordan Watkins and KhaDarel Hodge will have increased roles, while the 49ers' front office is "working on all possibilities, looking at everything that's out there" for possible outside reinforcements.

Also worth noting: Shanahan said the 49ers will have to manage the workload of wide receiver Mike Evans - who left Sunday's game with a hip injury - throughout practices this week. But it doesn't sound like his hip is a major concern at the moment.

As for the defensive line, Thompson's injury further damages the 49ers' interior depth, as it follows the season-ending injury to second-year defensive tackle Alfred Collins . Thompson, an undrafted rookie, rotated in for 19 snaps Sunday prior to getting hurt. The healthy defensive tackles on the 49ers' active roster are Osa Odighizuwa , Gracen Halton and CJ West. Halton, another rookie, had a standout performance Sunday and has already earned an increased role in defensive coordinator Raheem Morris' system.

San Francisco has the following players on IR who could be designated to return at some point: Stribling, WR Christian Kirk , OL Austen Pleasants, CB Nate Hobbs , LB Nick Martin and DL Sam Okuayinonu . It's unlikely all those players will be back on the active roster this year, but the first three are the most obvious candidates. Kirk is eligible to return to practice after the 49ers' Oct. 4 matchup against the Denver Broncos .