CHICAGO -- John Lackey will return to the Cubs' rotation on Sunday to face the Giants in the series finale, while Mike Montgomery will wait and see what's next for him.
Montgomery gave up three earned runs over four innings on Thursday against San Francisco in his third start for Chicago.
"It was one of those days when I wasn't quite sharp," Montgomery said Friday. "I don't know if it was a timing issue. It's just one of those things."
The Cubs may go to a six-man rotation and have Montgomery start again, or he could find himself in the bullpen. It doesn't matter to the lefty.
"My focus will be on getting my timing back," Montgomery said. "It can be a little frustrating at times, but at the same time, I know the season is long and there will be stretches when you're a little off, and it's just getting back to focus."
Lackey has been on the disabled list since Aug. 15 because of a right shoulder strain, and he threw a second bullpen session on Thursday.

• The Cubs have a significant lead in the National League Central, but manager Joe Maddon is not looking ahead to the postseason. So far, fans have not been asking him about the potential postseason roster.
"My conversations are, 'Good morning, nice game last night, coach' -- they call me 'coach' all the time," Maddon said. "A few really well-informed males call me 'Skip' once in a while. It's very complimentary. But no advice."
Does he understand the interest?
"That's what fans are supposed to do, and that's what [the media is] supposed to do," Maddon said. "It creates interest. I just can't be that guy. On the top of my [lineup] card every day, I write, 'Do not be a fan.'
"I think it's great that everybody is into us now, and there's that kind of talk at this time of year. I promise you I have not thought about it one time. It is about Friday."