Vick Ballard (ACL) out for season

INDIANAPOLIS -- The Indianapolis Colts' running game has taken a substantial hit.

Running back Vick Ballard will undergo season-ending surgery on a torn ACL in his right knee, coach Chuck Pagano said Friday. Colts owner Jim Irsay tweeted that Ballard has been placed on injured reserve.

Ballard, who as a rookie led the Colts in rushing last season, was injured in a non-contact drill during Thursday's practice. Pagano and teammates described the injured at "freakish."

"Nobody touched him," running back Ahmad Bradshaw said. "Everybody saw it. They just gasped. He was going through the hole on a team drill. He was trying to weave through the line. His foot got caught in the ground and it happened."

Ballard paced the Colts with 63 rushing yards in a 21-17 season-opening victory over the Oakland Raiders last Sunday.

"We all know Vick was headed toward having a fabulous year," Pagano said. "We know and understand injuries are part of this game. We'll deal with it. Nobody handles adversity quite like this team in this locker room. Vick will get through this, and with his mindset and his work ethic he'll come back stronger than ever in 2014."

The Colts had planned to team Ballard with Bradshaw, who signed with Indianapolis in the offseason, to give the offense a running duo to complement the receiving and tight end groups.

Now the load will go to Bradshaw, who sat out the entire preseason while recovering from offseason foot surgery, and Donald Brown. Bradshaw had seven rushes for 26 yards in the opener; Brown, who is in his fifth season, didn't receive a carry against the Raiders.

Indianapolis hosts the Miami Dolphins (1-0) on Sunday.

Information from ESPN NFL Insider Adam Schefter contributed to this report.