MTV Threatened To Replace The Situation

According to sources, producers from MTV and 495 Productions sat Situation down for the first time while shooting Season 2 in 2010 -- explaining his drinking had become such a problem ... it was making it hard to shoot the show.

We're told Sitch promised to pull himself together -- but it quickly unraveled during Season 3, and producers had to speak with him again ... this time threatening to replace him on the show if he didn't clean up his act.

Sitch agreed again -- and made a concerted effort to reel in his bad habits between Seasons 3 and 4. We're told Situation showed promise in Italy during Season 4, but once the crew got back to the States ... he was back to his old ways. This prompted another sit-down ... and another threat of recasting.

Now, MTV's got the opposite problem -- Situation's in rehab and sobering up completely. As a result, sources tell us 495 Productions is looking for new castmates to add to the show ... in the hopes of phasing Sitch out entirely.