The midfielder was off the pace against Wolves and then had to watch the draw against Liverpool from the stands because of the problem.
A concerned Sir Bobby told the Evening Chronicle: "We have booked Lee in to see a specialist in Cambridge on Monday.
"It's his hip, not his groin, and he is in quite a bit of trouble, but we will know better after Monday."
If Bowyer is ruled out over the Christmas period it will mean that the international midfielder currently holding down a position in the team, despite a string of poor performances, will almost certainly continue to play every match.