SAN FRANCISCO — Tim Lincecum will return to the mound today for San Francisco after the Giants ace missed his last start with spasms and inflammation in his lower back.

Lincecum (13-5) will pitch the opener of a key home series against the Colorado Rockies, who lead the Giants by 4 1/2 games in the NL wild-card race.

"This whole week's been big," Lincecum said yesterday after his team beat the rival Los Angeles Dodgers, 7-2, to avoid a sweep. "I'll be as ready as I should be. I'm going to take it out there like any other start and not put any added pressure on myself."

Colorado dropped the final two games at San Diego after winning eight straight.

The reigning NL Cy Young Award winner pitched eight scoreless innings and allowed only four hits in his most recent outing against the Rockies on Aug. 28 in San Francisco.

Lincecum tested his back by playing catch Friday, then threw a bullpen session Saturday. He said yesterday he felt fine and wasn't in any pain.

"He's good to go tomorrow," manager Bruce Bochy said. "Timmy feels fine. That's good news for us. We'll keep an eye on him."

Lincecum will enter his start as the new NL ERA leader at 2.34 after St. Louis' Chris Carpenter gave up seven earned runs in six innings against Atlanta in a 9-2 loss by the Cardinals yesterday.

"I feel better than I did yesterday," Lincecum said.