Janoris Jenkins will be in line to make his 49ers debut Thursday night. Not long after signing with San Francisco’s practice squad, the veteran cornerback is now on their active roster and in position to start his 11th season.

The 49ers made Jenkins one of their gameday elevations ahead of their Week 15 matchup against the Seahawks. The team also elevated Willie Snead and signed defensive tackle Akeem Spence to their 53-man roster. While Snead and Jenkins are gameday elevations, Spence moving up from the practice squad required a roster move. The 49ers placed D-lineman Hassan Ridgeway on IR.

A.k.a. “Jackrabbit,” Jenkins has not played since being a starter in the Titans’ divisional-round game against the Bengals last season. The Titans released the journeyman in March, and not much interest appeared to come Jenkins’ way this offseason. But San Francisco, which has dealt with multiple key injuries at the cornerback spot, added him on a P-squad pact in late November.

At 34, Jenkins is the league’s oldest active corner. He has been a full-time starter for the Rams, Giants, Saints and Titans. The former second-round pick has 27 career interceptions and eight pick-sixes, ranking in a tie for eighth in NFL history in the latter category. After being charged with six touchdowns and a 100.2 passer rating allowed while in coverage last year, Jenkins did not see the Titans follow through with the second year of his two-year contract.

The 49ers have lost Emmanuel Moseley and Jason Verrett for the season and are also down rookie Samuel Womack, who sustained a concussion against the Buccaneers.

Ridgeway suffered a strained pec and is set to miss six to eight weeks. The team had used the former Colts and Eagles defensive tackle as a replacement for Arik Armstead, who has since returned to action. Ridgeway, who made seven starts this season, went down while playing a reserve role in Week 13. The 49ers’ No. 1-ranked defense will be shorthanded at D-tackle. Not only are Ridgeway and Javon Kinlaw out, but starter Kevin Givens is down with an MCL sprain. Givens remains on San Francisco’s active roster but is set to miss time. With the 49ers prioritizing Kinlaw and Elijah Mitchell returns from IR, Ridgeway’s season might be over. Then again, Kinlaw has not returned to practice and cannot be considered a lock to return from IR given his knee trouble. Pro Football Focus ranked Ridgeway just outside the top 60 (out of 125 qualifiers) among interior D-linemen this season.