New York Yankees outfielder Clint Frazier (concussion) is beginning a rehab assignment with High-A Tampa on Thursday, according to a source. He will serve as the designated hitter and bat second for the first game of a doubleheader. Frazier has been dealing with post-concussion migraines stemming from an initial concussion he suffered back in spring training. He's been on the minor league disabled list since July 19. In 15 games with the Yankees this year, Frazier is hitting .265/.390/.353 with[...]