Giants' Lincecum left Game 2 with back tightness; unsure of availability for rest of series

San Francisco Giants right-hander Tim Lincecum isn't sure when he'll be able to return to the mound after leaving Game 2 of the World Series with tightness in his lower back, reports Andrew Baggarly of Comcast SportsNet Bay Area.

"It was nice to get out there and compete a little bit," said Lincecum, who made his first appearance of the postseason in Wednesday's 7-2 loss to the Kansas City Royals. "Outside of that all I can think about is just hurting myself."

The 30-year-old will undergo treatment Thursday for his ailing back, though he needs confirmation from a doctor that his injury is unrelated to his hip. Lincecum mentioned after the game that he's battled this kind of ailment before.

Lincecum, who last appeared in a game Sept. 28, retired all five hitters he faced before his back tightened up in the eighth inning, prompting manager Bruce Bochy to remove him from the game.