Vulnerable Rep. Joe Knollenberg (R) has brought on a new chief of staff, replacing his former top aide who recently took a leave of absence for personal reasons.

According to Knollenberg spokesman Steve Betz, Trent Wisecup left the office in early November. In mid-October, a YouTube video was posted by a liberal activist showing an irritated Wisecup screaming at the man on camera.

Soon after, local news outlets reported that Wisecup said he had been diagnosed with bipolar disorder and was taking a leave of absence from his duties as Knollenberg’s chief of staff.

Wisecup came on board with Knollenberg at the beginning of 2007. He worked for the eight-term Member earlier in his career as well, Betz said. Knollenberg has hired White House aide Craig Albright, his former legislative director and campaign manager, as his new chief of staff.

Knollenberg had his first close race in more than a decade in 2006 against radio host Nancy Skinner (D). Democrats consider the district a prime pickup opportunity and have put up former state Lottery Commissioner Gary Peters to run against Knollenberg. However, Skinner also is running again.

— Shira Toeplitz