I'm not sure, but it wouldn't surprise me at all. Video games are coded with numbers, so quite possibly if you have a much lower overall than the team you're playing, it could quite possibly make your team play worse. I dont know though.
On a side, get used to Palmer being hurt. I'm in year 5 with the Bengals and Palmer has made it through only 2 seasons w/o major injury. Draft a replacement high, and draft a replacement soon.
Only bad thing is Palmers ridiculous contract. I'd trade him, but the cap hit will be out of this world (20-something mill).