The 25-year-old told ESPN: "I'm on the record as saying Andrew Luck can be the greatest quarterback who ever played the game of football. I've seen him do some unbelievable things that I still can't believe a quarterback was able to do. I have tremendous respect for that guy.
"[Luck and Seahawks' QB Russell Wilson are] both very good quarterbacks. They're both highly intelligent, both make plays with their feet and both have great arms. I don't want to take it any further than that."
The Colts host the Seahawks this Sunday.