Mike 'The Situation' -- In Rehab For Alcohol -- Problems for 'Jersey Shore'

The Situation is in rehab not just for prescription drugs, but also for alcohol, TMZ has learned, and this turn of events could pose big problems for next season's "Jersey Shore."

Sources involved in the situation (sorry) tell us ... the Situation went through detox at a facility before he checked into Cirque Lodge in Utah, and the detox involved alcohol.

Our sources also say The Sitch is "very open" with other patients at Cirque about his drinking. He discusses how his club appearances escalated his alcohol use.

Now here's the problem for "Jersey Shore." The Situation and alcohol have been tied at the hip for 5 seasons. If the show allows The Situation to fall off the wagon to make the show better in season 6, they will look like crass enablers. If they don't let him drink, there's a good chance they will lose viewers.

Stay tuned.