“By the end of last season, Frank Ragnow’s injury report was long enough to need a deep breath to read through, listing issues with his toe, ankle, knee, and back. So, after the Lions’ NFC Championship Game loss to the 49ers, it wasn’t shocking when the three-time Pro Bowl center openly acknowledged the variety of injuries he faced. This led to some light speculation about retirement, which he quickly dismissed at the NFL Honors event.” But it’s fair to say some years have been taken off Ragnow’s career. Entering his…