The Colts' starting running back job is not up for debate: it’ll be Frank Gore. But the backup spots behind him? They’re completely wide open.

Gore is 33 years old, so not only do the Colts need to find players to back him up and provide a change of pace this year, they also need to be looking for players who could potentially replace him down the road.

The team signed Robert Turbin and Jordan Todman in free agency, while they're also bringing back Tyler Varga and Trey Williams. Perhaps the most interesting name, however, is an undrafted free agent signed out of Illinois: Josh Ferguson.

The Indianapolis Star’s Stephen Holder reported that the Colts gave “strong consideration" to drafting him but ultimately decided they could sign him as an undrafted free agent, which they did - with the help of a $10,000 signing bonus and $25,000 guaranteed, according to the National Football Post’s Aaron Wilson. That’s big money for an undrafted player, and it lends credence to those thinking Ferguson could wind up having a significant role in 2016.

“You know, again, it’s just in shorts, but he looks really good,” head coach Chuck Pagano said of Ferguson on Thursday as the team wrapped up mini-camp. “He’s smart. He picks things up in a hurry. He’s very, very athletic. He’s a great receiver out of the back field. We can split him wide, we can displace him formationally. He’s a mismatch out in space. He’s got juice. He can go. He’s got great vision. Just not a third down back but he’s a good runner. He’s explosive and twitchy and he’s got a jump cut that’s really, really good. The rubber will meet the road when we get to Anderson and we put the pads on and see if that play speed is the same.”

It’s hard to really tell much from running backs in mini-camp when players are working without pads or contact, but Ferguson certainly is someone to keep an eye on as we move forward. The Colts will be looking for someone to step up behind Gore, and it’s anybody’s guess who that will end up being. But since the Colts didn't add a back in the draft and only added a couple of smaller free agents, it paves the way for Josh Ferguson to be a prime competitor not just for a roster spot, but also for the number two running back spot.

Ferguson played in 47 career games at Illinois, racking up 4,474 total all-purpose yards. He rushed for 2,586 yards and 18 scores while averaging 5.1 yards per carry, and he also added 168 receptions for 1,507 yards and eight touchdowns (averaging 9 yards per catch). In addition to all of that, he also returned 21 kickoffs for an average of 18.1 yards per return. Ferguson also holds the school records for most career receptions and receiving yards by a running back.