Because there are as many as 4 position player spots that need to be filled and the team doesn't have this many pitchers with actual trade value to bring back major league starting pieces. Second base can likely be filled internally with some combination of Espinal, (assuming he isn't non-tendered), Biggio and Schneider, and maybe in a pinch Horwitz could fill the DH/backup 1B opening, but third base and left field both likely need to be filled with external players.