The injury bug that has decimated the San Francisco 49ers' linebacker corps has now taken a bite out of the most heralded backup. Rookie Chris Borland, who has flourished as Patrick Willis' replacement, is now also possibly lost for the season with an injury to his left ankle suffered in the Niners' 17-7 loss at the Seattle Seahawks on Sunday.
"It would be a stretch right now," Niners defensive coordinator Vic Fangio said Tuesday when asked if Borland would play again this season.
Also, the availability of outside linebacker Ahmad Brooks, who leads the Niners with six sacks but suffered a left thumb injury against the Seahawks, is uncertain.
Earlier Tuesday, the 49ers signed linebacker Desmond Bishop and placed receiver/special teams ace Kassim Osgood on season-ending injured reserve in the corresponding roster move. The Niners also announced the practice squad signings of tight end Xavier Grimble and cornerback Cameron Fuller.
The 49ers already had a pair of linebackers on their practice squad in Shayne Skov and Chase Thomas but instead chose to sign Bishop, who was released by the Arizona Cardinals on Dec. 1.
"We've just got to do our best to get him acclimated to the system," Fangio said. "He's going to have to do a great job of studying. Obviously, his work day is going to have to be a lot longer than everybody else's. Not on the field, per se, but studying in the classroom and watching tape and learning what he needs to learn to go out there and play for us on Saturday if needed."
The 6-feet-2, 244-pound Bishop, a sixth-round draft pick of the Green Bay Packers out of Cal in 2007, has started 27 of the 73 games in which he's played and has been credited with 318 tackles, nine sacks, seven forced fumbles and nine passes defensed. After six seasons in Green Bay, Bishop played for the Minnesota Vikings in 2013 before going to Arizona this season.
Fangio was also asked his thoughts on the play of Borland, who replaced Willis in Week 6 and has a team-leading 107 tackles.
"He's done extremely well," Fangio said of Borland. "He started off, when he came in for Pat late in the second quarter of that first game [at St. Louis] he played, he kind of just played and did fine. Then the next game, which was his first start [at Denver], he didn't play as well. And then from that point on, he has taken off and done well. He still makes some mistakes, still doesn't react well to certain plays and certain coverages the way he should consistently enough, but I think that will come.
"And, you know, I think we've got a player that nobody was so sure ... he could play at his collegiate level in the pros, and with his work this year he's proven that he can to some degree."