Cotton was five-plus innings into what was shaping up to be one of the best starts of his season when manager Bob Melvin and a team trainer emerged from the visitor's dugout. Melvin took one look at Cotton's hand and motioned for bullpen help.
The right-hander had just yielded his third hit of the night, a lead-off single to Kevan Smith, who was the last batter he faced before departing in favor of Liam Hendriks with a 3-0 lead.
Cotton, who had a 5.02 ERA in his five previous starts since returning from Triple-A Nashville, walked one and struck out three in the shortened outing.