T.I. is up the creek without a paddle — because TMZ has learned, prison officials in Atlanta have barred the rapper's lawyer from challenging the decision to put him back in prison.

The Federal Bureau of Prisons sent T.I.'s lawyer a letter yesterday, explaining the rapper was "not entitled to legal counsel" during the process by which officials review the decision to lock him up again.

T.I.'s lawyer originally sent the Bureau a letter last week, asking to be present at the hearings — but the Bureau flat out rejected him.

According to the Bureau's response, two hearings have already occurred without T.I.'s lawyer present — one last week and one the week before — but it's unclear what transpired.