Pretty cool: Before the Home Run Derby, each player signs all the balls they will hit.

See the pic below for an example. That one was hit by "Big Dumper" Cal Raleigh, with his jersey number, 29.

Side note: The fan was wearing an Apple Watch (so it seems).

https://www.cnn.com/2025/07/15/sport/home-run-derby-analysis-spt
#MLB#HomeRunDerby