New York Yankees pitching prospect.  Impressive pinstripe jersey worn by Whelan during the 2008 season with the Trenton Thunder, the Double A affiliate of the NY Yankees, number 23 on back, "Thunder" across the chest, 2008 Trenton Thunder 15th Season patch on the left sleeve, size 46, jersey made by Russell Athletic, signed by Whelan in blue felt tip on front of jersey.  The jersey has a Letter of Authenticity from the Trenton Thunder for the game use and a Certificate of Authenticity from Steiner Sports for the autograph