HOUSTON -- The Astros have invited 35 to 40 players to a pre-Draft workout at Minute Maid Park following Thursday's game against the Nationals. The Astros have four of the first 58 picks and five of the first 90 in the 2010 First-Year Player Draft, which begins Monday in Secaucus, N.J.

The regional supervisors -- Clarence Johns, Ralph Bratton and Mark Ross -- and southern California area scout Tim Costic have been meeting this week to go over the three different draft boards the Astros have pieced together at Union Station.

"Now it's a case of merging those lists and hopefully getting ready to take advantage of four of the first 58 picks in the Draft," general manager Ed Wade said.

Assistant general manager Bobby Heck and national cross checker David Post have been going over potential Draft picks, position-by-position, to ensure they're on the same page. The three Draft boards are broken down by West, Central and East regions, and they'll be merged with the top 100 players making it onto the main board.