Lincecum will get his final chance to impress before the playoffs Sunday when the Giants conclude their series against the Arizona Diamondbacks.
While it's been a frustrating season for Lincecum, he's pitched better in the second half after going 3-10 with a 6.42 ERA before the All-Star break.
Lincecum (10-15, 5.15 ERA) is 7-5 with a 3.67 ERA since and had won three straight decisions before struggling his last time out. He allowed seven runs -- all earned to tie a season high -- while walking four in four innings of a 7-2 loss to Arizona on Tuesday.
"This was one he has to put behind him because he's really done a nice job this second half," Bochy told the Giants' official website.
One thing Bochy does know is that he plans to use Hector Sanchez behind the plate for Lincecum on Sunday and likely in the postseason. He has caught Lincecum's last seven starts.
Lincecum is 1-1 with a 4.34 ERA in three starts against the Padres this year. He gave up four runs and five hits in six innings of a 6-5 loss at Petco Park on June 5, but didn't factor in the decision. He had a 1.77 ERA in his previous nine starts there.
The Giants (92-66) will try to bounce back after their three-game winning streak was snapped with a 7-3 loss Saturday.
The Padres (75-83) had dropped three in a row and scored nine runs over their previous four games. Headley's home run was his 30th and moved him into a tie with Milwaukee's Ryan Braun for the NL lead with 112 RBIs.
"It's exciting. I think at the end of the year I'll really be able to reflect about it a little bit more," Headley said. "It was a great feeling when I hit it, and it was an even better feeling coming in the dugout and having all the guys more happy than I was. That was really special."
Headley is 9 for 32 with two homers lifetime off Lincecum, going deep for one of his two hits in eight at-bats this year.
Edinson Volquez (11-11, 4.13) will take the mound for the Padres.
Volquez went seven scoreless innings in a 2-1 win over the Los Angeles Dodgers on Tuesday. The right-hander was 4-4 with a 7.27 ERA over his previous nine starts.
Volquez is 2-1 with a 5.54 in five career outings against the Giants, but was solid in a 3-2 loss July 24. He surrendered two runs and three hits while striking out eight in seven innings.
Posey, who is hitting an NL-leading .337 after going 2 for 2 Saturday before being replaced in the bottom of the sixth, was in the lineup after having a pitch bounce up and hit him in the throat Friday.
Copyright 2012 by The Associated Press
This story is from ESPN.com's automated news wire. Wire index
MORE MLB HEADLINES
- Ibanez among 3 finalists for Rays manager
- Dodgers go to familiar well, get Rays' Peralta
- Blue Jays GM: Martin 'key to our offseason'
- UCLA names sports complex after Robinson