Richardson's 3.5 yards per carry average for his career has been another target for doubts. But the running back played with broken ribs for much of last season and still managed to compile 950 rushing yards and 11 touchdowns.
He also caught 51 passes — more than Indianapolis' running backs combined in 2012 — for 367 yards and another score.
Grigson said the decision to acquire Richardson "just felt right," and he likes the running back's fit with the Colts.
"He loves football," Grigson said. "That's always a prerequisite for (head coach) Chuck (Pagano) and myself and Mr. Irsay. We want people that love what they do. People that are good at what they do love what they do. In that respect, he's, I believe, very talented, naturally. He has the right body type, I feel, for his style as a runner, and his style is what fits this offense."
Richardson also could benefit from better skill-position talent around him in Indianapolis.
In addition to Luck, he'll be playing alongside wide receivers Reggie Wayne and T.Y. Hilton as well as tight end Coby Fleener. Richardson also has a veteran mentor behind him in Ahmad Bradshaw.
But the transaction that made him a Colt came as a surprise.
He learned about the trade on the radio after receiving a phone call from a friend. And he said some of his first thoughts were about his children's school and other family related matters.
As the trade began to sink in, however, Richardson became more comfortable with the move.
"It's starting to wear off, but it's still a shock," he said. "At the same time, I'm ready to open this new chapter in my life, especially here with the Colts. It's a great surrounding, great coaching staff and a great locker room."