Once again, more bad injury news for the 49ers.
Cornerback Ahkello Witherspoon was placed in the concussion protocol Wednesday, The Athletic's Matt Barrows reported. The 49ers signed cornerback Brian Allen, according to his agent, in a corresponding move. Allen was signed to the practice squad.
Witherspoon going to concussion protocol comes the same day star cornerback Richard Sherman reportedly was placed on injured reserve with a calf strain.
If Witherspoon can't go, the 49ers' top two cornerbacks Sunday against the New York Jets would be Emmanuel Moseley and Dontae Johnson, who is on the practice squad. Jason Verrett did not practice last week due to a hamstring injury.
Witherspoon, a former third-round draft pick, only played four snaps on defense in the 49ers' Week 1 loss to the Arizona Cardinals. He also had played 13 snaps on special teams. The 25-year-old finished with one solo tackle in the loss.
Allen, 26, was a Pittsburgh Steelers fifth-round draft pick in 2017. He has played in 16 career games and has three tackles. Allen spent last season on the Seattle Seahawks' practice squad.
The 49ers need a win Sunday over the Jets, and their secondary took a tough hit Wednesday.