David Nevins, who exited his post as president of Imagine TV on Thursday, is set to succeed Greenblatt, according to the trade paper. Nevins is an executive producer on series such as Lie to Me and Friday Night Lights.
Greenblatt is credited with reinvigorating the pay cable channel and ushering in a new era of original series. Thanks to recent critical and commercial hits such as Dexter, Weeds, Californication, United States of Tara, and Nurse Jackie, Showtime has become a formidable competitor for longtime heavyweight HBO.
Earlier this year, Showtime took three of the four acting categories at the Golden Globes with wins for Tara star Toni Collette, and Michael C. Hall and John Lithgow, both for Dexter. Hall also picked up hardware at the 2010 Screen Actors Guild awards.
During Greenblatt's tenure, Showtime jumped from 12.4 million subscribers in 2003 to 18.1 million subscribers as of March, according to The Hollywood Reporter.
In December, the Season 4 finale of Dexter scored the channel's largest audience ever.