According to mlb.com, Carson has a brain tumor and used to play shortstop before his diagnosis.
He and Rangers third baseman, Michael Young, have crafted a special bond over the years.
"The chance to kind of spend and get to hang out for a day (with Carson) is something I've been looking forward to," Young said. "Hopefully he has been, too. It started out fun, and Carson got to throw out the first pitch. I've already given him a hard time to see if he can throw something I can handle, and we get to hang out during the game so it should be a lot of fun."
On Thursday, Carson threw out the first pitch of the game against the Oakland A's, which the Rangers won 8-5.