Softness aside, what's happening here is that the bright white uni against the bright white background makes everything flat and washed out. Nothing is jumping out.
I'll give you a break, but you did post it so I assume it's up for critique. There seems to be something funky going on with the blur in the background. Did you add blur in post? I'm referring to the darker line horizontally in the frame about his chin height and then what looks like a sharp edge to the blur at the edge of the grass. This must be a warm-up shot-cuz he's not on any mound? Try shooting some from a low angle to see if you like that perspective also. It's nice you can get some good shots of your grandson.
The actual photo shows the ball in a different position, and judging from the outfielder it is indeed a warm-up throw? As noted above, getting lower and shooting actual pitches yields a better shot? When I shoot softball pitchers I use High Speed Continuous and will normally get one shot that has the ball coming out of the pitchers hand in most sequences.
