The left-hander tossed 5 2/3 innings during Tuesday night's 4-0 victory over Baltimore, but he admitted after the game he was pitching on fumes.
There was a noticeable drop in Laffey's velocity, as he consistently threw only 82-83 mph, and while he should still make one more outing, his status will continue to be monitored.
"He's a little stiff, and that's to be expected," manager John Farrell said of Laffey, who has already thrown 100 more innings this year than in 2011. "He's kind of beat up a little bit in general physically, not any one specific area.
"[It's] not unexpected by any means, but we'll take every precautionary measure, every treatment available to him and see how he responds over the next couple of days and we'll determine his next time out."
If Laffey is unable to go, then his start likely would be given to Shawn Hill. The veteran right-hander's contract was purchased from Triple-A Las Vegas on Monday to serve as a long reliever and emergency starter during the final week of the season.
The need for Hill arose because Laffey and right-hander Carlos Villanueva have thrown a high number of innings this season. Both starters are battling fatigue due to the increased workload, and Hill serves as an insurance policy in case any changes need to be made.
"We knew at a minimum he would give us length out of the bullpen," Farrell said of Hill. "Knowing that the doubleheader was Monday, the condition of both Aaron and Carlos as we're getting to the end here, we felt like we needed a guy who could go three-to-four innings in an outing if the need arose."
Laffey has thrown 159 1/3 innings this year between the Majors and Triple-A compared to just 57 combined innings in 2011. He is 4-6 with a 4.52 ERA for the Blue Jays this season.