ESPN Dallas’ Mark Stein reports Major League Baseball has rejected a Rangers proposal to have Mavericks F Dirk Nowitzki  (above, left) throw out the ceremonial first pitch at one of their home games during the 2011 World Series.

Unlike regular-season games, all first-pitch assignments in the World Series have to be approved from a list of candidates by the league office.

Sources told that — with the NBA in the midst of a lockout that has spanned 111 days — at least some hesitation stems from the idea that MLB executives want to stand behind their basketball counterparts and have notified the Rangers that they can’t bestow first-pitch honors on an NBA player.

Major League Baseball insists that the NBA’s labor unrest had no impact on Nowitzki not being selected to throw out the first pitch.