The Colts are signing safety Mike Mitchell, a league source tells Tom Pelissero of NFL.com (on Twitter). Terms of the deal are not yet known, but it’s likely a low-cost one-year pact. 
Mitchell was one of several veteran safeties who were victimized by an uncharacteristically slow market for the position this offseason. The Steelers cut him loose in early March and nothing came of his multiple workouts. Mitchell tried out for the Cardinals in July, showed his stuff for the Titans before they signed Kenny Vaccaro, and worked out for the Bears and Bengals in September. Finally, Mitchell has an NFL deal, and it’s with the Colts.
Mitchell, 31, spent the past four seasons in Pittsburgh, where he started each of his 61 games. In 13 games last season, Michell finished with 53 tackles and two passes defended. Pro Football Focus ultimately ranked him 62nd among 87 safety candidates.
The Colts expect to have starting corners Quincy Wilson and Kenny Moore back from their concussion layoffs when they face the Jets on Sunday. Mitchell, meanwhile, will be on hand to provide depth in the middle of the field.
Mitchell gets a little bit of a bum rap from Steeler fans. Most would have you believe that he was terrible his whole Steeler career. In reality, he was worse than terrible in 2017, but very good in 2016 and at least average or better before that. Not sure if last year was because of injuries or if he’s lost a step. He hits a ton and does make receivers over the middle listen for footsteps, but he’ll take a dumb roughing penalty too.
The thing is, he would always go for the big hit, which yes would make him look great when he lands it, but more often than not he would miss, or only land a part of it, and thus allow a big play. And his penalties got frustrating after a while.
I don’t disagree with anything you said. The penalties got old, but on the other hand I think that after awhile he got a few called on him that were frankly ridiculous.