Safety Clayton Geathers will be placed on the physically unable to perform list, a designation that will carry through the start of the regular season.
Geathers, who had neck surgery in March, will miss at least the first six weeks of the regular season. He injured his neck on a fourth-down stop to seal the Colts' victory against the Tennessee Titans in Week 11 last season. Geathers missed the following game because of a concussion and eventually was placed on injured reserve on Dec. 12 with the neck injury.
Geathers tried every option possible before eventually deciding to have surgery in March, which has put him on the sideline the entire offseason.
The Colts spent the offseason reshaping a defense that finished 30th in the NFL last season, but not having Geathers for at least the first six weeks is a blow because he's the unit's most physical defender.
His versatility allowed defensive coordinator Ted Monachino to use him as a fifth linebacker last season, when Geathers had 59 tackles in just nine games.
Rookie Malik Hooker, the team's first-round pick, and veteran Darius Butler, who is making the transition from cornerback to safety, are the leading candidates to start at safety. General manager Chris Ballard likes the idea of having two free safeties playing together.
"I think in an ideal world you almost have two free safety-like players, two corner-like players who have some coverage ability," Ballard said. "So I think having both Malik and Butler out there gives you some flexibility on defense to be able to match up against spread formations."
Defensive lineman Kendall Langford, a projected starter, will also open training camp on the PUP list, but Ballard said he anticipates Langford being ready for the start of the regular season. Langford missed nine games with a knee injury last season.