Ted Purdy carded a 5-under-par 65 in the opening round and was joined in third place by David McKenzie, Bob Burns and D.A. Points. Cameron Beckman, Dean Wilson, Charley Hoffman and Shigeki Maruyama were one stroke further back at minus-4.
Rose started on the back nine of the Resort Course at LaCantera Golf Club. He carded a birdie on the 11th, but gave that stroke right back when he bogeyed 12.
The 26-year-old birdied the par-5 14th and made the turn at minus-2 thanks to a birdie on No. 18. Rose also birdied the first.
Rose posted back-to-back birdies from the third to move to 5 under. He tripped to a bogey at the fifth, but recovered that stroke with a birdie on seven. Rose finished at 6 under after he dropped in a 6-foot birdie putt on the ninth, his last.
'I have been playing well the last three weeks, and I guess my one concern has been running out of steam and stuff like that,' said Rose, who has finished in the top 14 in each of his last three starts. 'I'm back in the tournament from the word go.'
Cejka, who has just two top-10s in 25 starts this year, got on the board with a birdie on the par-3 third. He later picked up birdies on five and seven to head to the back nine at 3 under.
The 35-year-old parred three straight before a birdie on No. 11. Cejka birdied the par-5 14th and joined Rose in the lead as he converted a 5-footer for birdie on the par-4 18th to cap a bogey-free round.
'Basically, the second half of last year I was playing hurt,' said Cejka, who is still coming back from a jet-ski accident some 15 month ago. 'But I was ready at the beginning of this season and I'm playing better than my results have shown. The longest birdie putt I had today was 25 feet. The rest, I hit it pretty close.'
Former world No. 1 David Duval shot a 3-under-par 67 and is tied for 11th. Duval was joined there by Bob Tway, Ryan Hietala, Richard S. Johnson, Justin Leonard, Frank Lickliter and Ryan Palmer.
Defending champion Robert Gamez opened with a 1-under-par 69 and is tied for 30th place.