Allen suffered a hip injury in last week's win over the Oakland Raiders, leaving the game after scoring a 20-yard touchdown. It was his only catch of the game. He didn't practice at all this week and is unlikely to suit up for Week 2.
Allen is entering his second year in the NFL. He recorded 45 catches for 521 yards and three touchdowns in his rookie year while splitting time with fellow rookie Coby Fleener.
If Allen is inactive on Sunday, the Colts will be down to Fleener, Jack Doyle and Dominique Jones on the depth chart. Offensive coordinator Pep Hamilton may be forced to abandon his favored two tight end sets and go with more three wideout formations. T.Y. Hilton could see more playing time than he did last week.