Kelly will serve as the Red Sox's opening pitcher for Sunday's game against Cincinnati, Christopher Smith of MassLive.com reports.
Kelly will make his second start of the season Sunday, likely throwing only 1-to-2 innings before handing the ball off. It's unclear if the Red Sox will commit to a full bullpen game or utilize a bulk reliever, though Chase Anderson would be the likely option to work extended innings behind Kelly if Boston elects to go that route.