I'm sorry, but this is just mind-bogglingly false. The Colts offense is friendly to RBs? Maybe back in 2004. Since 2008, it's been utterly lost for the below reasons, and it isn't on Addai....
First off, the Colts have one of the worst offensive lines in the NFL. It's been that way since about 2008. It's no coincidence that 2006 was Addai's best year. It's when they still had Tarik Glenn. He retired. Since then, it was a revolving door of utter crap.
Second -- if you've followed the Colts offense -- you'd know that their entire rushing attack hinged around the stretch play. You know, the very rushing concept that they stopped running since 2008. Why? Well it started when Peyton was coming back off of that knee injury; the bursa sack infection, remember? They tried to phase out the stretch because Peyton couldn't physically get out far enough to deliver the handoff. But after Peyton's knee healed? They really never returned to the stretch play because their line, at that point, had deteriorated. They really didn't have linemen who could get out of their stance, stretch horizontally, and execute a zone blocking concept. Again, for the past few years, Indy has had one of the worst lines in the NFL.
Also, Indy's offense was probably the most rigid and strict, in terms of which concepts they used. When they couldn't even run their most successful rushing concept? Their running game fell off a cliff....
EDIT: Oh, the reason why the Colts rushing attacked hinged on the stretch was due the defensive front 7 spacing. If you hit up defenses with the stretch enough; they'd widen their spacing to counter it. The result? First, obviously, it allowed the offense to gash that D right up the middle with another run. But more importantly, it meant the DEs or OLBs would be split out and, thus, further away from Peyton Manning; allowing him just a little bit more time. That's Toom Moore's offense in a nutshell. Simple concepts. But ones that can be used at any time, and are frustrating to defend....until the offense simply cannot execute it on their own (see, 2008-11).