49ers keeping Allen among four QBs in building an option

SANTA CLARA — The 49ers have four quarterbacks in training camp, and coach Kyle Shanahan is finding practice snaps for each of them. It appears to be a certainty the 49ers will keep three quarterbacks on their 53-man roster. But keeping all four - unless one is on the practice squad - is out of the question. "I think four on a 53 would be very challenging," 49ers general manager John Lynch said Monday. "Four in the building is certainly possible." After the cut to 53 players, teams are allowed to sign 16 unclaimed players to the practice squad. A quarterback could be in line for one of those spots on the practice squad. Brock Purdy is slated to be the team's starter with Trey Lance and Sam Darnold competing for the second spot. Veteran Brandon Allen still is getting daily practice snaps as the fourth in line. Lynch said no decisions have been made on how the 49ers will sort out their entire quarterback depth chart. "It's one of those things, I think we just want to throw it all out there, let things unfold, and then we'll figure out the details as we go," he said. Last year, the 49ers had injuries to Lance and Jimmy Garoppolo, which led to Purdy getting his chance in Week 13...