The defender was replaced by Scott Golbourne just after half hour with Shrewsbury 1-0 up against Oxford on Saturday with what appeared a muscle injury to his upper leg.
Grenada defender Pierre already had strapping to his thigh but, according to boss Sam Ricketts, came through the warm-up OK but felt the injury after Daniel Udoh's 12th-minute opener.
Pierre has been a regular in Shrewsbury's defence this season. His side went 2-0 up against the U's shortly after he left the field but, following Josh Vela's red card for two bookable offences, the visitors staged a turnaround and claimed three points through Josh Ruffels winner two minutes from time.
Ricketts said: "Aaron was fine in the warm-up but after his first goal he came over and said he could feel his muscle injury a little bit.
"We said to keep an eye on him but then five or 10 minutes later he needed to come off. We lost a centre-back, we lost a player through a sending off, get 2-0 and everything starts going against us.
"We'll find out how he is after he goes to have a scan on Monday."
One fitness boost for Town was the return of attacker Conor McAleny to the bench from a hamstring injury.
"He could've come on," Ricketts said. "Unfortunately we had to use all the subs up by then, it would've been a good one to get on."