PITTSBURGH — So much for retirement. Again.

Five-time Pro Bowl linebacker James Harrison is returning to the Pittsburgh Steelers. The 36-year-old Harrison signed a two-year deal with the team on Sunday following a productive 2014 in which he had 5½ sacks after being lured out of a brief 18-day retirement.

Harrison tweeted “I’m back” while posting a picture of him signing the deal to Twitter.

The 2008 NFL Defensive Player of the Year began a training program when the offseason began and was weighing another run in Pittsburgh or joining former Steelers defensive coordinator Dick LeBeau in Tennessee.

The signing gives the Steelers needed depth at outside linebacker after Jason Worilds abruptly retired at 27 two weeks ago rather than try and land a massive payday.

Harrison joins Jarvis Jones as the only players with more than nominal NFL experience at the position on the roster, though the team figures to grab at least one more edge pass rusher in the draft.

The timing also gives Harrison months to prepare for a 13th NFL season. He admitted it took him a handful of games to get into proper shape when he rejoined the Steelers last September.

Once he found his legs, however, Harrison showed flashes of the man who was among the league’s most feared players during his prime. He had two sacks in consecutive games in victories over Indianapolis and Baltimore at midseason.

Harrison, who turns 37 in May, is second in Pittsburgh history with 69½ sacks. His 17 multi-sack games are a team record.