Anderson, Ind. - The injuries are already piling up in Indianapolis.

On Thursday, the Colts put starting left guard Donald Thomas - a former All-Big East performer at UConn - on season-ending injured reserve with a torn right quad, the same diagnosis that ended his 2013 season after just two games.

The move comes one day after running back Vick Ballard had season-ending surgery to fix a torn left Achilles' tendon. And training camp is barely a week old.

"Donald worked extremely hard just like Vick to get back. We feel awful for Donald just like Vick," coach Chuck Pagano said after a morning walkthrough. "Donald will be fine. He is a strong-minded young man and will go back to work to rehab."

But that's no consolation to the 6-foot-3, 303-pounder who was trying to come back from the torn quad and a torn biceps.

He was injured late in Wednesday's practice after he wound up in a pile on the ground. The frustration showed immediately as Thomas slapped the ground and then limped behind a wall of teammates.

As he attempted to walk off the injury, he grabbed his head with both hands and walked from the far end of the practice field all the way to the locker room.

Colts officials had hoped for the best, but a late-night MRI confirmed their worst fears - Thomas had re-torn the same quad.

By Friday morning, Thomas was loading his belongings into his truck bed and preparing to head home from Anderson University.

"He's a tough guy. He goes out there with a chip on his shoulder every day and he competes and he plays hard through the whistle, that's one thing I really admire about him," rookie Jack Mewhort said. "Like I said, it's very unfortunate just because he was having such a great camp and he's a heck of a player."

Indianapolis thought Thomas' return would help solidify an offensive line that couldn't stay healthy, struggled to open running lanes and allowed far too many hits on franchise quarterback Andrew Luck in 2013.

General manager Ryan Grigson rebuilt the line again during the offseason. He released center Samson Satele and allowed starting guard and backup center Mike McGlynn to walk away in free agency, signed former Chicago Bears guard Lance Louis and drafted Mewhort in the second round and Ulrick John in the seventh.

Now it looks as if they'll need even more help.