The 600-card Base Set of 2010 Upper Deck was originally meant to be Series 1 only with a second series to follow later. However Series 2 was never released (and likely not produced). As with previous releases of Upper Deck, the set was primarily organized by team except for the subset which were not. Subsets included Star Rookies (1-40), Ballparks (541-570), and Team Checklists (571-600). There 25 variation cards sprinkled throughout the set at varying levels of rarity. Unlike Topps variations from the same time period, there was no theme to the variations. With the Variations included, the total number of cards in the set reaches 625.