The show's executive producers Mark Wahlberg and Doug Ellin have previously suggested that the series will end next year.
However, Grenier told Popeater: "Every end is really just a beginning. I think there's definitely some resolutions happening, but I don't see it as an end. I see it as a new dynamic."
He continued: "I think it could go on and on. I think Doug Ellin really shoots from the hip a lot. He's sort of an improvisational thinker. He's almost a medium who channels pop culture. So I think it would be really hard for anybody to predict exactly what's going to happen."
The seventh season of Entourage continues on Sundays at 10.30pm on HBO.