T-Mobile is a GSM Carrier, which means that they use SIM Cards. The Precedent doesn't have a SIM slot, as it runs on Straight Talk's CDMA-S (Sprint) Network.
Like prepaidguy9081 said, you can flash it if you know enough about CDMA Workshop.
Verizon and Sprint are Code Division Multiple Access (CDMA) technology. AT&T and T-Mobil are Time Division Multiple Access (TDMA) technology. GSM is on a totally different level than TDMA. (It's like saying that your car doesn't run on gasoline, it has an FM radio.) GSM is the name of the technology used in 2G, it has nothing to do with how the channel is divided for access.