In FO's running back rankings, there's Thomas at the top of DVOA, and third in Success Rate, which measures the consistency of a back's performance on a play-by-play basis. So, we know that Thomas is valuable per play, and play after play. What makes him special, and an asset for the Saints in the Super Bowl?
Thomas has great short-area speed to be sure, and that's a big deal against an Indianapolis Colts front seven that plays as quickly as any in the NFL. Against Minnesota's quick and brutally physical defense in the NFC Championship game, Thomas gained 61 yards on the ground against the NFL's best run defense and 38 receiving yards (one pass, five great moves, one touchdown) to top it off. When Drew Brees(notes) and Sean Payton throw all those three- and four-wise sets at enemy defenses, it's generally Thomas in the backfield, forcing defenses away from committing entirely to the aerial attack. As much as he benefits from those defenses backing off and playing pass, he also averaged 4.9 yards per carry on 50 carries in formations with only two wide receivers. And that's the myth of the Saints -- people assume that because Brees is among the best quarterbacks in the game and the offense scores so often, the Saints aren't a physical team. Thomas ran behind two-tight end sets 60 times and averaged six yards per carry.
Keep in mind also that only the Miami Dolphins ranked higher in Adjusted Line Yards. It isn't just the aerial attack, or the tight ends making the tough catches underneath, or Reggie Bush(notes) doing everything everywhere all of a sudden. It's also about a little-known guy, rising up from the ranks of the undrafted, and making things happen for his offense.