ANDERSON, Ind. – The immediate reaction to the news of Vick Ballard’s season-ending Achilles injury is that Indianapolis Colts general manager Ryan Grigson needs to look outside of the organization to find another running back to replace him on the roster.

Grigson is working the phones, but at the same time don’t be surprised if he doesn’t make a splash move like he did last season in acquiring Trent Richardson from Cleveland shortly after Ballard tore his ACL in practice last September.

“Ryan and I are discussing roster mechanics as we speak and we’ll make a decision,” Colts coach Chuck Pagano said. “We’ll check and see who is available and what’s best for the team and what gives us the best chance to win and see if we need to get some legs to gut us through camp and try and get someone in here with the opportunity to compete and make a roster.”

Ballard’s season came to an end when he tore his left Achilles during a non-contact drill in practice Friday.

If the Colts do look on the outside for help, some notable veterans available include Ronnie Brown, Felix Jones, and Willis McGahee. They also have time to wait and see which players get released later in training camp.

As far as internal options go, Chris Rainey and Daniel “Boom” Herron will have an opportunity to show if they're capable of being the Colts' third running back behind Richardson and Ahmad Bradshaw.

Rainey and Herron got plenty of opportunities to get snaps in practice Saturday because Richardson (precautionary) did not practice for the second straight day and Pagano doesn’t want to overwork the 28-year-old Bradshaw.

“Whatever the coach wants me to do,” Herron said. “I am just out here working as hard as I can just to make the team and help the team out.”

If you had to give the edge to either Rainey or Herron, you’d have to say Rainey has the advantage because of his versatility. He can return punts and kickoffs. The Colts signed Rainey in November 2013, but his season came to an end less than three weeks later because of a foot injury. He averaged 7.3 yards on his four punt returns and 21.8 yards on six kickoff returns.

“He’s going to help us in the return game and that’s going to give him a chance to make this team,” Pagano said. “You can see the athleticism, the burst, the speed. He puts a foot in the ground and gets north and south.”