Weston Richburg has been an integral part of the 49ers offensive line since the organization signed him as a free agent in March of 2018.
The 29-year-old started 13 games for the 49ers in 2019 before going down with a torn patellar tendon during the San Francisco's shootout win over the New Orleans Saints in Week 14.
As Richburg continues to rehabilitate, the 49ers placed the center on the Physically Unable to Perform list at the start of training camp. In speaking with The Athletic's Tim Kawakami last week, general manager John Lynch sounds confident that Richburg will be back this season, but likely will be out for an extended period to start the 2020 season.
"You know that's a tough rehab, it really is," Lynch said on "The TK Show" on Thursday. "We have to remember he came off a torn quadriceps the year before, so you take all that into account. Is it doable? Certainly, and Weston is on a good track. I think (The Athletic 49ers reporter Matt Barrows) Matt's depiction is probably accurate, we're probably looking at a PUP situation where he can open his window after Week 6."
The timing of Richburg's injury being so late in the season makes a Week 1 return much more difficult. Although Lynch expressed confidence Richburg would be ready for training camp back in April, it sounds like he hasn't progressed as quickly as initially hoped. If players are placed on the reserve/PUP list at the start of the regular season, teams can't activate a player for the first six weeks.
After that, teams get a five-week window to decide whether or not to bring that player back to practice. Once a player returns to the practice field, teams get a three-week window to decide whether or not to bring that player onto the active 53-man roster. If either window lapses, that player stays on the list for the rest of the year.
Ben Garland served as a valuable replacement for Richburg after his injury last season, starting the remainder of the year at center, including in Super Bowl LIV. But Garland went down with an ankle sprain in practice last week that Lynch said could sideline him for "a couple weeks."
San Francisco's depth on the offensive line and at wide receiver already is being tested early in training camp, and Lynch will have to trust that the reserves he's brought in can fill in admirably.