INDIANAPOLIS -- A work in progress.

You don't want to hear those words uttered when the start of the NFL regular season is less than two weeks away.

But wait.

That's not the worse part of it.

Indianapolis Colts coach Chuck Pagano was asked about the team's running game and he said, "it's going to be a work in progress the whole season."

The whole season, and he's not even specifically talking about running back Trent Richardson. Pagano was talking about the whole unit.

The Colts will be fine when it comes to their passing game, but they need some kind of production out of running backs Trent Richardson, Ahmad Bradshaw and Daniel "Boom" Herron to keep the defense honest.

Indianapolis is averaging 3.5 yards a carry as a team in the preseason while also dealing with injuries at center and right guard in the preseason. Starting center Khaled Holmes has missed the past two games with an ankle injury and guard Jack Mewhort missed a game with a knee issue.

"I don't think it's where we want it," Pagano said about their ground game. "I think we're headed in the right direction. ...We're still working at it. We've had some lineup changes, obviously, on the offensive line. We went through a whole season last year with that, from a continuity standpoint getting those guys together. We got (tight end) Dwayne (Allen) back."

Quarterback Andrew Luck added, "We know if we want to be a consistently good offense we have to be balanced. We have to throw, we have to run. It takes everybody."

Richardson's struggles from last season still remain, as he's only averaging 2.6 yards an attempt in the preseason. Bradshaw made his preseason debut against the New Orleans Saints last weekend.

Herron has been the most effective running back for the Colts in the preseason. He's rushed for 104 yards, including a 43-yard run against the Saints, on 18 attempts. The majority of Herron's yards, though, have come against backups. He's also returning kickoffs.

"I don't look at it that way," Pagano said. "I just know Boom has had a really good camp and a good preseason. He's made some nice runs. It's comforting knowing that you have a guy that not only excels on special teams, but you've got another guy in the backfield that can run and get yards for you when you need them."

Herron entered training camp as a longshot to make the roster, but a season-ending torn Achilles by Vick Ballard and Chris Rainey's immaturity, which is why he was released, has allowed Herron to put his skills on display even more.

"It's a great opportunity right now for me," Herron said. "I come here every day like it's my first day and the coaches know nothing about me. I try to work as hard as I can and just try to showcase what I can."