Upton, along with teammates Chris Young and Aaron Hill, took to the visitor's batting cage at PNC Park at 11 p.m. ET on Tuesday to take some hacks.
Though some who have not spent time around Upton might question his work ethic, putting in extra time and taking his work seriously is nothing new for him. In fact, if anything, he is too hard on himself at times, which is why manager Kirk Gibson was pleased to see that the late-night session was not overly serious.
"[He] just went in there and hit some and had a good time, which is good," Gibson said. "They just went in there and had fun, they went in there and mashed. Just uninhibited [and not] stressing out about it."