Boston reportedly likely just wanted to give Lackey a rest heading into the postseason. He is not suffering from any known injuries. It's possible that Lackey could still throw a simulated game on Sunday to keep his arm loose moving forward.
The Red Sox locked up the top seed in the American League on Saturday night, making Lackey's scheduled Sunday start less important.
Lackey has been one of the Red Sox best starters in the regular season, earning a 3.52 ERA and 1.16 WHIP over 29 starts. He will be tasked with continuing his success in the playoffs for Boston.
The Red Sox will play the winner of the one-game wild card playoff in the Divisional Series. That series will begin with two games in Boston on Oct. 4-5.