The San Diego Padres have reinstated right-hander Sean O'Sullivan from paternity leave and optioned right-hander Miles Mikolas to Triple-A Tucson.

O'Sullivan's wife, Sabrina, gave birth to their first child, Hailey Marie, on Wednesday.

O'Sullivan is 0-2 with a 3.72 ERA in four games, including three starts, with his hometown Padres this season.

Mikolas was recalled from Tucson on Tuesday for his fourth stint with the Padres this season. He's pitched a scoreless 1 2-3 innings in two games this year.