They lost 5 current players - 2 P, 2 OF and their starting C. Anthony Renaudo, of course, was the Red Sox' contribution to that number. But check out the lost signees they were counting on...
Delino DeShields, Jr. - 2B - 1st round signed with Astros
Zach Lee - P - 1st round signed with Dodgers (penciled in as #2 SP AND he was the backup QB on the football team)
Cameron Bedrosian - P - 1st round signed with Angels (likely RP)
Garin Cecchini - SS - 4th round signed with Red Sox (penciled in as starting 3B or 1B)
Lucas LeBlanc - OF - 11th round signed with Red Sox (penciled in as starter in OF)
That means they lost their 3 SPs, their 3 starting OFs, the 3B (or 1B), and the C. TOTAL LOSS - their starting rotation and 5 of the 8 position players. Oh, and a RP and a backup 2B who, at the very least, come from major league heritage. Ouch.