He batted only .252 last season with 45 K's to just 18 walks and a .328 OBP. One bright spot however, is the 21 stolen bases which put him 2nd on the team behind Ben Revere's 40. So as long as he can get on base, he can make some things happen on the base paths. Mastroianni's defense isn't anything worth noting, however, and is a far cry from the glove work of Span or Revere.
Defensively, Hicks is ranked as the top outfielder in the Twins farm system and has the best outfield arm. In high school he was clocked at 97 mph as a pitcher.
Of course, throwing a rookie in the starting lineup can always be a crap shoot, but if he's ready, Hicks could be a viable replacement to Span and Revere.