According to a press release issued by the commissioner's office, the players tested positive for a metabolite of Boldenone, a banned substance.
Galvez and Tineo, both 18, were signed in the Dominican in 2007. Florentino, 23, was signed in the Dominican in 2006. The players have yet to make their U.S. debuts.
Florentino was 6-1 with a 3.43 ERA and nine saves in 30 appearances in the DSL this summer. Galvez appeared in 16 DSL games and was 1-2 with a 2.52 ERA. Tineo appeared in 17 games in the DSL and was 1-3 with a 5.40 ERA.