Lacey signed a one-year contract with Buffalo on Thursday.
Lacey, who was an exclusive-rights free agent, comes cheap and will contribute at a high level on special teams.
Lacey is considered likely to land on the Bills' final roster due to his importance on special teams, Mark Gaughan of The Buffalo News reports.
Although he only logged three defensive snaps as a rookie last season, Lacy was still active for all 16 games due to his role as a core special teamer. He lined up for a team-high 285 special teams snaps in 2017, roughly 65 percent, and looks likely to see a similar role this year. However, it remains to be seen if the reserve linebacker will get more of an opportunity on the defensive side of the ball.
Lacey signed a contract with the Bills on Thursday, Mike Rodak of ESPN.com reports.
The Bills cut Lacey just one day earlier to make room on the roster for waiver claim Tyrell Adams, but the team ended up reversing the transaction after Adams failed his physical. Lacey will thus stick around for the Bills as Sunday's matchup with the Buccaneers approaches, but he'll be limited to nothing more than a special teams role if he's active for that contest.