Lester, who will start for the A's in the American League Wild Card Game on Tuesday, will oppose a Royals team that he's prospered the most against in his nine-year Major League career.
Lester owns a 1.84 ERA in 13 starts vs. Kansas City -- the lowest ERA against any team he's started at least six games against in his career. This includes three dates with the Royals this season, when he compiled a 2.61 ERA in two starts with the Athletics and one with the Red Sox.
"We know we have a tough situation with him," Royals outfielder Alex Gordon said on Monday. "We faced him three or four times this year and he's been tough on us every time. So it's going to be a fight, but we're up for the challenge."
Lester's ridiculous numbers against the Royals look less impressive when isolated to his five career starts at Kauffman Stadium, where he has a 3.10 ERA, including one start with Oakland.
Gordon opined that the steady dose of Lester over the years could even help his club.
"The more you face him, the more you know what he's going to do with you," Gordon said.
While Lester's regular-season stats usually line up with that of a top-line starter, the postseason is his sanctuary. Lester proved that in 2013, when he guided Boston to a World Series title with a 1.56 ERA in five postseason outings.
Lester has allowed just one run in two World Series starts.
"Last year if David Ortiz hadn't done what he did, Jon Lester would have probably been the World Series MVP with the way he steps up in the postseason," Royals manager Ned Yost said.
Lester enjoyed his best year as a Major Leaguer in 2014 with a 2.46 ERA. He rounded out the regular season in exceptional form with 11 straight quality stars after being traded to Oakland.
"These guys will be watching film of his last three or four starts. But they know he's tough, he's like [Royals starter] [James] Shields. These type of games he's tough as he can be," Yost said.
Jackson Alexander is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.