Five things you need to know about the Colts:

1. Quarterback uncertainty: A lot of people are saying Peyton Manning will start the opener, no matter what. Really? No matter whether doctors advise against it? I don't think so. He's driven, for sure, but he's not putting himself at medical risk. I expect we may not know his status until 90 minutes before the Sept. 11 game in Houston kicks off. In the meantime, late addition Kerry Collins provides an upgrade at backup. He needs better protection and a better run game than Manning's been getting in recent years to have a chance at success.

2. Stopping the run is key: The Colts failed to stop Arian Foster in the opener a year ago. They'll face the same challenge at Reliant Stadium on Sept. 11, followed by Peyton Hillis, Rashard Mendenhall, LeGarrette Blount and Jamaal Charles. Is the front good enough to stop those types of runners? It needs to be, especially if the offense isn't primed to run out to the sort of leads that prompt opponents to stop running it. Additions like Drake Nevis, Jamaal Anderson and Tommie Harris may help the front be better overall.

3. Special teams, with benefits: The new kickoff rule won't make kickoffs obsolete the way many doomsayers are predicting, but it certainly will make them less important. This is a great thing for the Colts, who regularly underachieve on special teams. Pat McAfee will bury a high percentage of kickoffs in the end zone and the team's lack of a consistent return man won't matter as much. When Manning is in place, the offense will happily take the ball at the 20-yard line at the start of most drives in exchange for not suffering as it did on Antonio Cromartie's big return late in the playoff loss to the Jets. McAfee's used that big leg to become adequate at long-range field goals. Once they are out of Adam Vinatieri's range, they could try the punter in desperate situations.

4. Depth a concern: Indianapolis has unproven depth at both safety and corner, and injuries akin to last year's could really leave the Colts exposed. They let Kelvin Hayden go in a salary-cutting move. That leaves them with Jerraud Powers, Jacob Lacey and Justin Tryon as their top-three corners, with untested Kevin Thomas fourth. They re-signed Melvin Bullitt to play safety alongside Antoine Bethea, but all the options behind them are young and haven't done much. It could be an issue.

5. Short-yardage offense: Joseph Addai can be effective in all situations, but he'd likely benefit and be fresher later in the season if he played fewer snaps. When the Colts are moving the ball, they go no-huddle and trap opponents in personnel packages, unable to substitute. The thing is, they are also unable to substitute. The Colts might do well to pause a bit more often to get rookie Delone Carter on the field to give them their best cracks on third-and-short and near the goal line.

-- Paul Kuharsky, ESPN.com

One of the weaknesses of the Colts' secondary last season was with deep passes over the middle, and the team didn't make any significant personnel changes there. Indianapolis elected for continuity over improvement at safety by re-signing Melvin Bullitt. Kelvin Hayden's release left a hole at cornerback that sixth-round draft choice Chris Rucker won't be likely to fill.

• The Colts were so bad against the run in the 2010-11 season that teams didn't bother to disguise their intentions. When opposing offenses lined up with multiple running backs in the backfield, the Colts ranked 28th in the NFL, allowing 4.6 yards per rush. Free-agent acquisitions (DT Tommie Harris, LB Ernie Sims, DE Jamaal Anderson) plus rookie defensive tackle Drake Nevis should provide some muscle against the run.

• While blitzing Peyton Manning is generally regarded as a bad idea, manufacturing pressure with a four-man pass rush didn't yield results, either. Last season, Manning threw 25 touchdown passes against four or fewer rushers, tops in the league, and the Colts' offensive line allowed six sacks all season against a four-man rush (fewest in NFL). Opposing defensive coordinators will have to hope for growing pains from rookie tackles Anthony Castonzo and Ben Ijalana, who may be forced into early action with left tackle Charlie Johnson's move to Minnesota.

-- ESPN Stats & Information