Jennings simply could have received a second opinion to confirm he's ready to return. It could be a sign the injury hasn't healed correctly. The problem has lingered longer than expected.
"The plan with Greg just from Day 1 was to try to get as far into the week because with his type of injury, the fatigue, going through the testing and him maxing it out," McCarthy said Monday. "The fatigue part of it, we felt sending him out for a bunch of practice was probably not in his best interest for the week he comes back."
Quarterback Aaron Rodgers and the Packers' offense have found their groove over the last two weeks after an uncharacteristically slow start to the season. Wide receiver Randall Cobb has filled in nicely while taking part in an increased role in the offense. And there's time for Jennings to rest if he needs it with the Jaguars, Arizona Cardinals and a bye making up the next three weeks for the Packers.
UPDATE: McCarthy confirmed later Wednesday that the team had Jennings seek a second opinion on his injury because they're concerned about the pace of healing, according to the Green Bay Press-Gazette's Mike Vandermause.
Follow Kareem Copeland on Twitter @kareemcopeland.