This is a 26-week, multicenter, randomized, double-blind, placebo and active comparator-controlled, parallel-group study in subjects with type 2 diabetes currently sub-optimally controlled by diet and exercise or with non-thiazolidinedione antihyperglycemic monotherapy. Pioglitazone is used as active comparator. The total duration of a subject's participation will be approximately 30 weeks, including a 2-week placebo lead-in period, a 26-week double-blind treatment period, and a 2-week post-treatment follow-up period. Subjects who complete the randomized portion of the study per protocol may have the opportunity to continue in a long-term extension study of active treatments.