San Francisco Giants righthander Tim Lincecum has no structural damage in his tight back and is expected to be available when the World Series resumes with Game 3 on Friday night.

“That’s the plan,” athletic trainer Dave Groeschner said via text message late Thursday with word an MRI exam on Lincecum’s back was all clear.

The two-time NL Cy Young Award winner was walked off the field by Groeschner during the eighth inning of San Francisco’s 7-2 loss at Kansas City in Game 2 when his left lower back tightened. Lincecum retired five straight before exiting during Salvador Perez’s at-bat.

Before Lincecum had further tests, the Giants were waiting to find out how serious the injury was and whether they would have to replace him on the World Series roster. He played catch at AT&T Park early Thursday evening once the team returned to the Bay Area from Kansas City.

“Timmy feels pretty good today,” Giants manager Bruce Bochy said Thursday. “If something’s going on, then it’s obvious we’ll have to make the change. But my hope is he’s fine, and if he is, then I think he’ll be good to go tomorrow.”

Lincecum hadn’t pitched since Sept. 28, not called upon out of the bullpen during the NL Division Series against Washington or the NLCS versus St. Louis. Lincecum missed pregame introductions before Game 1 Tuesday because he was vomiting.

Lincecum said after Wednesday’s loss at Kauffman Stadium that he didn’t think the long layoff contributed to tweaking his back, noting he experienced more tightness than pain. He felt his back tighten up on the lower left side on one pitch “and it didn’t look so good so I decided to stop.”

Lincecum said his back felt better Thursday than it did after the game, even after the long flight home.

“Sitting on the plane was a little iffy. I just did my best to try to stay stretched out and keep it loose,” he said. “We’ll see how it progresses. It feels better than it did yesterday. We still have to wait and see.”

The 30-year-old Lincecum pitched the Game 5 World Series clincher at Texas and was a key reliever during the 2012 title run and fourgame sweep of Detroit. While Lincecum pitched his second no-hitter in 11 months against the Padres on June 25, the struggling four-time All-Star was moved to the bullpen in late August.

“It showed that he continued to work in the bullpen,” Bochy said. “He had a great session three days ago, so he showed good command. He looked comfortable out there. So I didn’t like the score, but I was glad I was able to get him out there and get him some work. I know he has to feel good about that outing. I know we do, so he could play a bigger role now if he’s healthy.”