Showtime’s brass are really happy with the premiere of its comedy veteran series Californication on Sunday. So happy that they have renewed it for Season 5 after one airing. The cable network’s new entertainment president David Nevins just made the announcement at the pay cable network’s TCA session. On Sunday, Californication’s (848,000) fourth season debut delivered the dark comedy series’ best series premiere ratings ever. Additionally, Showtime announced a greenlight for new unscripted series featuring behind-the-scenes access with the 2010 World Series champion San Francisco Giants. The series, which will chronicle the Giants’ quest to defend their title through the 2011 MBL season, is done in a collaboration with MLB Prods. Showtime also announced premiere dates for Nurse Jackie and The United States of Tara (March 28) and new drama The Borgias (April 3).