"Unfortunately, after the victory in Seattle, I caught a spare champagne bottle to the elbow bone," McCullers said.
McCullers said he had some swelling after the incident following the team's 18-inning, ALDS-clinching win over the Seattle Mariners, so the team chose to give him an extra day to rest.
"It was really no one's fault," McCullers said. "It was just an accident. So it's not a huge deal."
McCullers said he threw a bullpen of 35 pitches Friday, was feeling good and would have no limitations in his start Sunday.
Asked exactly how the injury occurred, McCullers said, "Some guy was kind of coming back behind me and the bottle just happened to kind of hit the back inside part of my elbow as the people were passing by. It wasn't like we were getting wild. I was standing there. He was walking by, just happened to hit me in the right spot."
McCullers isn't the first pitcher to be injured celebrating this postseason. Philadelphia Phillies reliever David Robertson missed the National League Division Series after straining his calf jumping to celebrate a home run by Bryce Harper in the wild-card round.
Javier pitched 1 1/3 innings of relief in Houston's 8-7 Game 1 victory in the ALDS but hasn't started since an Oct. 1 win over the Tampa Bay Rays.
Primarily used as a starting pitcher, the 25-year-old Javier was 11-9 with a 2.54 ERA and 194 strikeouts in the regular season.
On June 25, Javier, Hector Neris and Ryan Pressly combined for the first no-hitter at Yankee Stadium in 19 years in Houston's 3-0 victory. Javier, whose fastball topped out at 96.3 mph in the game, set career highs with 13 strikeouts on 115 pitches over seven innings before he was pulled. Gerrit Cole, who will start for New York on Saturday, took the loss in that game.
McCullers started Houston's marathon 18-inning win over Seattle in Game 3 of the division series that completed a sweep of the Mariners. He allowed two hits and struck out seven in six scoreless innings of the 1-0 victory before being injured as the Astros celebrated clinching their sixth straight trip to the ALCS.
He ended Game 7 of the 2017 ALCS by throwing 24 consecutive curveballs to retire the Yankees' final five batters in order.
McCullers did not make his season debut for the Astros until Aug. 13 because of a right flexor tendon strain. He went 4-2 down the stretch with a 2.27 ERA and 50 strikeouts this season.
The Yankees had already tabbed Cole as the starter for Game 3 and Nestor Cortes for Game 4.
The Associated Press contributed to this report.