NEW YORK -- Gerrit Cole tossed from the bullpen mound on Friday afternoon before the Yankees' game with the Blue Jays at Yankee Stadium and said he expects to return to the rotation on Sunday against Toronto.

The reigning American League Cy Young Award winner was scratched from a scheduled start on Tuesday in Philadelphia with what the club described as "general body fatigue." Yankees manager Aaron Boone also said that Cole had been dealing with a stomach virus.

Asked what he needed to feel in order to return to the mound, Cole told reporters: ¡°Better.¡±

Cole has said that he had difficulty bouncing back physically from his previous start against the Mets on July 24, when he was hammered for six runs and eight hits in 5 2/3 innings, including three homers.

"I feel very fatigued,¡± Cole said on Tuesday. ¡°I¡¯m grinding a little bit.¡±

That prompted the coaching staff to shuffle the Yankees' rotation, offering the right-hander extra days. Right-hander Will Warren made his Major League debut in place of Cole, permitting four runs in 5 1/3 innings as the Yankees defeated the Phillies, 7-6, in 12 innings.

Cole is 3-2 with a 5.40 ERA in seven starts since returning from a right elbow injury that interrupted his spring, surrendering nine homers in 35 innings.

A healthy Cole will be vital to the Yankees¡¯ postseason drive, especially considering the club fell short in its efforts to add a starting pitcher in advance of the Trade Deadline.

Yankees general manager Brian Cashman said that he pushed hard to obtain right-hander Jack Flaherty, but he was unable to complete a deal with the Tigers, who instead dealt Flaherty to the Dodgers.

Cole will thus be counted upon to lead a staff that also has seen Carlos Rod¨®n, Marcus Stroman and Nestor Cortes struggle at times over the past six weeks, while Luis Gil has thrown a career-high 112 2/3 innings.

Clarke Schmidt, who hasn¡¯t pitched since late May due to a right lat strain, is scheduled to toss live batting practice session early next week and could be available to help at some point in August.

Speaking after the Deadline, Cashman said that he was optimistic Cole will be the staff ace that they need him to be down the stretch.

"This guy is clearly an important piece,¡± Cashman said. ¡°He knows there¡¯s a bigger prize we¡¯re playing with. I appreciate, and [pitching coach] Matt Blake appreciates, the relationship, the dialogue and the ability to pivot with these five off-days coming up in August.¡±