Klein announced Tuesday that he was retiring from the NFL, Alaina Getzenberg of ESPN reports.

EDGE Analysis

Klein will retire after playing 11 seasons in the NFL for five different teams. The 33-year-old, who was a free agent before announcing his retirement, most recently played for the Bills, where he played in two regular-season games during the 2023 campaign but failed to record any stats.

The Bills elevated Klein to the active roster Saturday.

EDGE Analysis

Klein played a key role in the Bills' win over the Steelers in the wild-card round after the team suffered several defensive injuries. He ended up playing 67 percent of the defensive snaps -- his first action since Week 10 against the Broncos -- while recording a game-high 11 tackles. With Matt Milano out for the season and Baylon Spector ruled out for Sunday due to a back injury and starter Terrel Bernard (ankle) listed as questionable, Klein may be asked to step up again, a task that will be a little more difficult against Patrick Mahomes instead of Mason Rudolph.

Klein (back) was a full participant in Friday's practice.

EDGE Analysis

Klein had been dealing with a back injury that held him out of the Bills' Week 9 loss to the Bengals, but it now seems as if he's had enough time to move past the issue. The veteran linebacker has appeared in only one game for Buffalo this season, playing strictly on special teams.

Klein (back) was a limited participant in Thursday's practice.

EDGE Analysis

Klein popped up on Buffalo's injury report last week with a back issue, and that injury ended up holding him out of the team's Week 9 contest. The 32-year-old linebacker was able to log a limited practice session Thursday, and with the Bills playing on Monday night, he's got a chance to suit up for Week 10.

Klein (back) has been ruled out ahead of Sunday's game against the Bengals, Alaina Getzenberg of ESPN.com reports.

EDGE Analysis

The veteran linebacker suffered a back injury during Wednesday's practice that held him out both Thursday and Friday, so it's not a surprise that he's been ruled out ahead of Sunday's contest. Klein has appeared in only one game for Buffalo this year, playing 14 special teams snaps during the team's Week 8 win over the Buccaneers.

Klein suffered a back injury Wednesday and will not practice Thursday, Chris Brown of the Bills' official site reports.

EDGE Analysis

The veteran barely sees the field on defense these days, but he's still a strong special-teams player at 32 years of age and saw action on 54 percent of the special-teams snaps in last Thursday's win over Tampa Bay. The Bills don't have much depth at linebacker following a major injury to Matt Milano (leg) in Week 5, so they might have to promote someone from the practice squad if Klein can't play Sunday night in Cincinnati.

The Bills signed Klein to their active roster Wednesday, Maddy Glab of the team's official site reports.

EDGE Analysis

Klein joined Buffalo's practice squad back in September but will now be added to the active roster. The 32-year-old could start at linebacker for the time being with Matt Milano (knee) on injured reserve, although rookie Dorian Williams also has a chance to earn the role.

Klein was signed to the practice squad Thursday, Alec White of the Bills' official site reports.

EDGE Analysis

Considering how inexperienced the Bills are at linebacker following the free-agency departure of Tremaine Edmunds, it was a bit of a surprise the veteran Klein -- who is also a good special teams player -- was cut ahead of the season. We wouldn't be surprised to see him suiting up for Buffalo before the end of the season.

The Bills signed Klein to a one-year contract Monday, Grace Heidinger of the team's official site reports.

EDGE Analysis

A season ago, Klein played in two games for the Ravens, two matchups for the Bears and six contests as a member of the Bills. The 31-year-old linebacker is currently heading into his 11th NFL campaign, and he's once again in a position to compete for a starting gig in 2023.

Klein recorded nine tackles in Thursday's 28-25 win over the Lions.

EDGE Analysis

Klein made his debut with the Bills after being claimed off waivers Nov. 17. He was on the field for 100 percent of defensive snaps and finished second on the team with nine stops. So long as Tremaine Edmunds (groin) remains sidelined, Klein figures to have a significant role in the middle of the Buffalo defense.