With zero advance promotion, KRON tonight filled anchor Tom Sinkovitz’s (right) seat on the anchor desk with Chris Murphy (left), a Bay Area native who has been at Channel 4 for four years. Sinkovitz, longtime co-anchor with Pam Moore on the 6 and 11 p.m. news, announced Friday that he was leaving the station after 17 years. On Friday, Sinkovitz suggested he was headed to another local station. During tonight’s 11 o’clock news, no mention was made of Murphy’s promotion, although sports anchor Gary Radnich looked at the other three people on the set and declared, “You guys are young. Pam just belies her age. I’m now like the oldest guy at KRON. I’m the only guy who limps at KRON. … I used to be young and frisky.” Murphy grew up in the Bay Area, and worked at stations in Bakersfield, Eureka, Reno and Portland before joining Channel 4. Here’s his bio. For the past four years, Murphy has been on Channel 4’s morning news. But he’s lucky. The show has changed its starting time from 5 a.m. to 4 a.m. at the same time Murphy is leaving for the evening newscasts.