O'Sullivan's scheduled start for Triple-A Pawtucket was skipped Thursday, Peter Abraham of the Boston Globe reports.
The Red Sox have been getting by with four starters during their most recent turn through the rotation, but will need a fifth starter Sunday and it looks like skipping O'Sullivan's start Thursday makes him an option. He had a brief turn earlier this season for Boston and was eminently hittable in two starts, giving up 19 hits and 10 runs (nine earned) in 11.1 innings. Aaron Wilkerson is also an option to be called up, however. After Sunday, scheduled days off and the looming All-Star break will allow Boston to get by without the need for a fifth starter until July 24.