INDIANAPOLIS -- Defense has been the theme of the Indianapolis Colts' offseason so far, as they've signed six outside free agents and kept cornerback Darius Butler.

The Colts could have as many as four new starting linebackers by Week 1 of next season. And while getting help in the pass-rush department continues to be a need, finding a second cornerback is up there on the list, too.

It’s high enough that you can't completely rule out the possibility of Indianapolis using its first-round pick -- No. 15 overall -- on a cornerback in an attempt to find a starter to go alongside two-time Pro Bowler Vontae Davis from Day 1.

“You look at the draft, this is a really deep draft when it comes to the secondary,” Colts coach Chuck Pagano said. “You’re going to get a good player, maybe a couple of them. Then it’ll be up to us how quick we can develop those guys and get them on the field. There’s going to be growing pains. Great speed, guys with ball skills, guys that have skill set you’re looking for.”

The Colts have long searched for the right player to go with Davis on the outside. Greg Toler was talented, but he missed 14 games with injuries during his three seasons with the Colts. Indianapolis replaced Toler with Patrick Robinson last season and, well, Robinson was basically Toler Part II, playing only seven games due to an assortment of injuries. The Colts released Robinson last month.

The Colts started five different players at cornerback in 2016. They even had veteran Antonio Cromartie on the roster before he was released after their Week 4 game in London.

Indianapolis has Rashaan Melvin, Darryl Morris, Charles James II, Tevin Mitchel, Christopher Milton and Frankie Williams as other cornerbacks currently on the roster. That group combined for just one interception last season.

If -- and it’s just an if at this point -- the Colts decided to select a cornerback in the first round, Mel Kiper and Todd McShay have Ohio State’s Marshon Lattimore and Gareon Conley, Washington’s Kevin King and Alabama’s Marlon Humphrey as first-rounders in their latest mock draft.

Butler likely isn’t an option to start on the outside because not only has he been more comfortable playing in the slot, but the plan is for the Colts to move him to safety.

“He’s been back there and he’s been effective at the nickel spot,” Pagano said. “He’s effective as a blitzer, he’s been effective in coverage. If he’s got to go back there and be a full-time safety, he’ll playing football. It’ll be good for us.”