FORT MYERS, Fla. (AP) – Red Sox right-hander Justin Masterson threw 81 pitches over 4 2/3 scoreless innings at Boston’s minor league complex Thursday afternoon.

Masterson allowed four hits and two walks. He struck out six.

He threw 81 pitches, 50 for strikes.

In five Grapefruit League games this spring, he has made three starts. The Red Sox have opted to keep him stretched out in case he is called on to start early in the season.

The lack of definition for his role does not seem to faze Masterson.

“That’s really cool that there’s a spot, and it gives me some confidence as we go out here to just continue to get better even as we’re continuing to get higher pitch counts and more innings,” he said.

In 2008, Masterson appeared in 36 games for the Red Sox. He went 6-5 with a 3.16 ERA in nine starts, including his big league debut in an emergency start April 24, where he pitched 6 innings and allowed a run, before moving into the bullpen in July.