Source : Webster's Revised Unabridged Dictionary (1913)

Texas Leaguer \Tex"as Leagu"er\ [From the Texas (baseball)
   League.] (Baseball)
   A short fly that falls too far out to be handled by an
   infielder and too close in to be caught by an outfielder.
   [Cant]

Source : WordNet®

Texas leaguer
     n : (baseball) a fly ball that falls between and infielder and
         an outfielder