Mackenzie Hughes withdrew from the Travelers Championship on Thursday after opening in 6-over 76, citing illness.

Turns out, it was a little more than that.

Hughes revealed Thursday evening on Twitter that he is actually dealing with a kidney stone. The 32-year-old said he started discomfort in his right lower back on his charter flight from Los Angeles to Connecticut last Monday.

"Once we took off, though, the pain was unbearable," Hughes said. "I went to the front of the plane and laid down on the floor, but nothing was helping. The pain was so bad it made me nauseous, and I started throwing up."

Hughes remained on the airplane's floor for the entirety of the five-hour flight, and once the plane landed, Hughes was rushed by ambulance to a nearby hospital, where a CT scan showed a 4-millimeter kidney stone.  Hughes was prescribed pain meds and ordered to rest until the stone passed. He tried to play, but he only got through 18 holes.

"Unfortunately, I haven't passed it yet," Hughes said, "and I am still dealing with lots of discomfort."