His status is not the only health question mark as the Colts prepare to face the 1-0 Dolphins. Inside linebackers Kavell Conner (ankle) and Jerrell Freeman (quad) also did not practice Thursday, and outside linebacker Erik Walden (hamstring) was limited.
Inside linebacker Pat Angerer has fully participated the past two days and appears ready to return to his starting role after missing the Raiders game while recovering from a concussion. Kelvin Sheppard likely would make his second straight start at the other inside spot if Conner and Freeman are unable to play against Miami.
Rookie Bjoern Werner likely would start in place of Walden.
Allen's absence could be felt most of all, however, especially in light of owner Jim Irsay's tweet on Wednesday demanding better protection for Andrew Luck. The second-year quarterback was sacked four times against the Raiders and hit a total of eight.
Allen is confident the Colts can get their protection issues ironed out and keep Luck upright this week, even against a fierce Dolphins pass rush led by defensive end Cameron Wake.
"I feel week-by-week our communication is going to get better," he said. "It was just a communication thing out there this weekend that we obviously didn't do well since Andrew was sacked four times and hit eight. Mr. Irsay said it best, our priority is to protect Andrew. That's what we're going to do going forward."