Entering play on Friday, Curtis Mead has been the best offensive player in all of Spring Training. He is hitting .778/.810/1.000 with a MLB leading 382 wRC+; Mead has a 14.3 BB% and 4.8 K%, both are staggering differences from his career norms, as is his 5.1 WHIFF%, which is half of what his WHIFF% has been in the big leagues.
Of course, this is only over 21 plate appearances and Spring Training statistics are next to meaningless.
The Rays best hitter last year in spring training with at least 20 plate appearances? He hit .333/.417/.714 with a 193 wRC+; it was Nick Meyer, a Mets prospect on a minor league invitation.