A slightly torn hamstring will keep Addai out two to four weeks, and to compound the problem rookie backup Mike Hart landed on injured reserve (knee). Though the Colts are a decidedly pass-heavy team, Addai's absence will hurt in numerous ways that go beyond the team having to settle for the services of a less-gifted runner.
Addai is a steady, productive receiver out of the backfield and an excellent blocker in Indianapolis' blitz pickup schemes. His versatility helped keep defenses from keying on personnel groupings or formations, and he gave quarterback Peyton Manning nearly unlimited flexibility to audible (which he does frequently).
And because Addai's gifts -- great vision, burst and inline agility -- mesh perfectly with the Colts' run scheme, production on the team's signature stretch play could suffer. Any dropoff would carry over to the passing game, in which Indy runs a lot of play-action from stretch looks. Moreover, the absence of an effective ground attack could put more stress on Manning (still recovering from multiple offseason knee surgeries), a banged-up offensive line and a struggling defense.
Dominic Rhodes is a capable replacement, and his vast experience in Indianapolis' scheme will help. But he lacks Addai's great burst on the second level and isn't as effective in pass protection. Plus, he will have to carry the load without a proven backup on the roster. The Colts are likely to acquire either second-year back Clifton Dawson, rookie Chad Simpson or both. Neither has the burst, speed or instincts to replace a healthy Addai. Even if the team wanted to tweak the scheme to better suit the new runners, the offensive line was built for the zone blocking scheme. Besides, none of Addai's potential replacements is likely to deliver his level of production (2,842 total yards and 23 touchdowns in his first two seasons) in any scheme.
When the Colts run now, expect more quick-hitters between the tackles. At 203 pounds, Rhodes isn't big or powerful, but he runs downhill and hard and has the speed to break long gains if he finds a crease. Overall, though, they're likely to throw even more frequently, possibly rolling out more nickel packages on early downs and going with a condensed passing package. Defensive coordinators will use Addai's injury as an opportunity to unleash a variety of pressure packages, multiple fronts and disguised coverages on one or more untested backs. Indianapolis will have to counter by limiting the pass-protection calls and adjustments.
The necessary changes to the Colts' run game, option routes and pass protections likely will make for a more vanilla offense. Unfortunately, that's life without Addai.