Harrison said he had a rough couple of days with vomiting and other symptoms, including last Wednesday, when he started against the Red Sox at Fenway Park and allowed four earned runs and eight hits in 4 2/3 innings.
He acknowledged that the stomach ailment, which he picked up by way of his wife Meghan by way of their 1-year-old daughter Addie, did impact him against Boston.
"Some of the pitches I made weren't very good," Harrison said. "Definitely my energy level wasn't there. I feel good and I'm ready to go in New York."