Upton, 21, struggled the final few weeks of Spring Training and the initial two weeks of the regular season before finding his stroke at the plate. In fact, his resurgence can be traced to an at-bat that occurred April 14 against the Cardinals.
In an eighth-inning at-bat in that game, Upton fell behind 0-2 in the count, battled back to 3-2 and was then hit by a pitch. Conor Jackson followed with a big homer and the D-backs went on to finally win in 10 innings.
"That kind of got me into the mindset I'm in now which is that I'm not worrying about mechanics," Upton said. "In that at-bat I was just worried about getting on base and I forgot everything mechanically and I actually felt comfortable at the plate. Letting my athletic ability take over is going to be big for me and not worrying so much about the result. Just focusing on having a good at-bat."
Prior to that, Upton was focused on making mechanical adjustments at the plate, because it was said he wrapped the bat too far around his head in his stance.
Upton hit .373 during May with a .709 slugging percentage that included eight doubles, four triples, seven homers and 21 RBIs.
Upton hit two homers in a game twice during the month, the first on May 6 at San Diego and then on May 20 at Florida. The second homer in Florida was a 13th-inning game winner.
Steve Gilbert is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.