Just after WWE Monday Night RAW, former WWE Champion John Cena announced on twitter that he will be undergoing an MRI scan on his left knee. Here?s his tweet: I am headed to grand rapids right now for early morn MRI on left knee. @wwe no matter what the result, I will be in the ring tomorrow! — John Cena (@JohnCena) November 20, 2012 We sincerely hope that nothing?s serious there.