Castle Season 6 Cast Joshua BittonCastle‘s 12th precinct is fortifying its ranks as Season 6 opens, with the addition of an ambitious new crimesolver.

TVLine has learned that Joshua Bittonhas been recruited to guest-star in multiple episodes as Grant “Sully” Sullivan, a new detective who is trying to prove himself at the 12th Precinct.

Bitton’s TV credits include appearances on Vegas, Private Practice, Justified and the HBO miniseries The Pacific, where he played Sgt. J.P. Morgan.

Castle returns with its new season on Monday, Sept. 23.