There weren't too many surprises among the best offensive players in September 2010, with many elite players simply continuing their excellent play(Pujols, C. Gonzalez, Tulowitzki, A-Rod, Holliday, Crawford, Votto).
There were other well-known but somewhat surprising players mixed in as well (Mark Ellis, Kelly Johnson, H. Matsui). There were also some surprises, which included players that have been around for a while like Ryan Raburn, but also some rookies who had played well all year but took their play to another level in September.
Top rookies: September 2010
Mike Stanton (Marlins, 21): .316, 8 HR, 19 RBI
Pedro Alvarez (Pirates, 23): .311, 5 HR, 26 RBI (T-2nd)
Ike Davis (Mets, 23): .344, 31 H, 16 R
Mike Stanton: .259, 22 HR, 59 RBI, 396 PA
Pedro Alvarez: .256, 16 HR, 64 RBI, 386 PA
Ike Davis: .264, 19 HR, 71 RBI, 601 PA