Wouldn't the confusion have been instantly ended, if Lou Costello had asked Bud Abbott to spell the first baseman's last name?

Costello could have said, “Hey Abbott, how do you spell the first baseman’s last name?” Abbot would have replied, “W-H-O” and Costello would have said, “Oh! So his last name is WHO! I get it!” (This could have been saved until the very end, so the comedy wouldn’t be ruined. It might have helped give the routine some kind of “closure.”)

After all, the routine did end with Costello describing a series of plays, correctly naming all of the members of the team, didn’t he?