CHICAGO -- An emotional Jon Lester took the mound Wednesday night for what could have been his final start at Wrigley Field as a Cub.

Lester, 36, will be a free agent after this season unless the team picks up a $25 million option on him for 2021.

"We don't know what the future holds," Lester said after the Cubs' 3-2, 10-inning win over the Cleveland Indians. "A lot of emotions going into tonight. Trying to make tonight go well. ... Maybe the effort was a little too much."

Lester threw only 62 pitches, giving up two runs over five innings. With a road trip to finish the season looming and the possibility that he'll be the third starter in the postseason, Wednesday could have been his last outing at home in a Cubs uniform. The first round of the playoffs is best-of-three, and then all remaining postseason games will be played outside of Chicago.

"A lot of things on my mind," Lester said. "This year hasn't been easy for a lot of reasons. I'm not sitting here saying 'woe is me' because there's a lot of people worse off than me. A lot of emotions coming into this. Don't really know what to say, how to take it. A lot of uncertainties going forward."

Lester signed a six-year, $155 million contract with the team before the 2015 season and then helped the Cubs to four consecutive playoff berths and the 2016 World Series title. In Chicago, Lester is known as one of the best free-agent signings ever.

He said he wanted to walk off the mound to a stadium full of Cubs fans in his last start, but it wasn't meant to be this year.

"That's the most frustrating part," he said. "Going back to 2014, I didn't get to walk off the field like I wanted to at Fenway. Having an empty stadium [is] not how I envisioned my last start here."

The door isn't closed on Lester as a Cub, but with so much uncertainty, the team wanted to recognize a player who will go down as one of the all-time greats in the organization.

"You just have to absolutely acknowledge that it could be," teammate Jason Heyward said of this being Lester's last outing. "He's earned that and some. It really, really is unfortunate we don't have fans here this year to help be a part of that. This is something he's earned. This dude has been a rock here."

Lester's career ERA is 3.59, but it's a run lower in the postseason. He has 192 career wins but just two this year. He'd like to win No. 200 as a Cub, but he's unsure what the future holds.

"A lot of uncertainties going forward," Lester said. "I didn't think six years would go this fast."