McClellin, 23, was a first-round selection of the Bears in the 2012 NFL Draft, but he recorded just 2.5 sacks as a rookie in a reserve role. He is undergoing treatment for the injury, but it will not require surgery to repair and isn't expected to keep McClellin from attending minicamp that is scheduled to begin on Tuesday.
Plantar fasciitis is an inflammation of the tissue on the bottom of the foot but can be controlled with stretching, ice and rest. Bears defensive end Julius Peppers played through the injury in 2012 and finished the season with 11.5 sacks and a trip to the Pro Bowl.
McClellin was awarded the Piccolo Award in April, an annual honor given to the Bears rookie that best exemplifies "the courage, loyalty, teamwork, dedication and sense of humor of Brian Piccolo," a former Bears running back that died in 1970.