Sorrentino, 29, checked into an inpatient treatment program to get help with substance abuse issues, sources told the celebrity website.
But a rep for the reality star would only say he "has spent the past several weeks at an undisclosed location for much needed rest and recuperation after his extensive production and appearance schedule."
MTV announced this week that Sorrentino and the rest of the "Shore" crew had signed on to a sixth season of the popular series.
"Getting in amazing shape for season 6!" Sorrentino tweeted to fans Monday.
Production for the show will begin in Seaside Heights, N.J., this summer.