I had no idea such an item existed. Oh the wonders of ebay!
To promote the US release of Rockman Soccer, Capcom apprently distributed MegaMan themed soccer balls:
"This auction is for a “SNES Megaman Soccer Ball promo from Capcom. This item came from the Capcom vault a few year back and I was lucky enough to get two, one for me the other for the winning bidder. It was used to promote the release of MEGAMAN SOCCER for the Super Nintendo. The ball is made of a hard sponge like material and is about 7 inches in diameter. Please note that this is not a real soccer ball but a RARE PROMOTIONAL PIECE that was used to promote the SNES Game MEGAMAN SOCCER."
Cool. Personally, I'm not a big soccer fan (nor am I a fan of RM Soccer), but this may interest some of you.