If gossip magazines like Us Weekly are accurate, Matt Kemp and his famous singing girlfriend Rihanna have broken up.This should come as welcome news for many Dodgers fans who believed Rihanna was the reason Kemp regressed last season.There wasn't much evidence for this theory, other than A+B must equal C. Kemp wasn't spotted out at clubs with her into the wee hours of the night, or in the recording studio early in the morning with her, or any other activities that would indicate he wasn't getting his rest. In fact, in mid-December Kemp was maintaining his all-day workouts in Arizona, when he could have been jet-setting around the world as Rihanna promoted her most recent album, "Loud." For whatever it's worth, there was a quote in Us Weekly from one of...