Yankees fans boo Gerrit Cole off mound after another poor outing

The Yankees' $324 million man allowed four runs on six hits. He also walked three and struck out six. 

Sunday's game against the Mets was Cole's worst start since signing with the Yankees before last season and his shortest start since he went just two innings on Sept. 12, 2016 as a member of the Pittsburgh Pirates. 

To make matters worse for Cole, Sunday’s crowd was the largest at Yankee Stadium this season.

Cole has not been the same pitcher since Major League Baseball began enforcing rules prohibiting pitchers from using sticky substances. While Cole has never been caught or reprimanded for using foreign substances, he wouldn't deny doctoring baseballs with Spider Tack last month. 

Minnesota Twins third baseman Josh Donaldson also named Cole when discussing pitchers doctoring baseballs.

"Is it coincidence that Gerrit Cole's spin rate numbers went down after four minor-leaguers got suspended for 10 games? Is that possible? I don't know," Donaldson said in June, according to the New York Daily News. "Maybe. At the same time, with this situation, they've let guys do it."

The 30-year-old entered Sunday's game with a 4.56 ERA over his last five starts. He had a 1.78 ERA at the end of May, but left Sunday's contest with a 2.91 ERA.

Cole isn't the only Yankee struggling, though. The entire team has been very inconsistent this season as New York entered Sunday fourth in the AL East, 9.5 games behind the first-place Boston Red Sox. 

Yankees chairman Hal Steinbrenner recently said he would consider exceeding MLB's luxury-tax threshold to help his club by this month's trade deadline. However, MLB insider Mark Feinsand believes a sale is possible if things don't improve in the Bronx, with players on expiring contracts, such as Corey Kluber and Brett Gardner, being the first to go.