Jonathan Netwon / The Washington Post

The Nationals sent Bill Bray down to minor league camp last week to work on his mechanics in a less stressful environment, still hoping they can use him in the majors once he improves. The Nationals will have until the middle of the season to do so or risk losing Bray.

According to a person familiar with Bray’s contract, his opt-out date isn’t until June. (The exact date wasn’t immediately available.) The Nationals can keep Bray in the minors until then, working with his mechanics and restoring his delivery. Once that date hits, however, Bray has the option to leave and sign with another team.

With a summer opt-out date, the Nationals don’t have to rush to decide what to do with Bray. He could still return and compete for a spot on the opening day roster. Bray, who in his six-year major league career has held left-handed hitters to a .218 average, came into camp as the leading candidate to serve as the Nationals’ lefty specialist.

Over the winter, he signed a minor league deal with an invitation to major league camp, and the Nationals hoped he could re-gain the form that made him a top left-handed reliever when healthy. Bray missed almost all of 2012 with a groin injury with the Cincinnati Reds and has been unable to regain his mechanics, particularly his arm slot. His velocity has been near 90 to 91 miles per hour this spring, in line with his career average and not in the high 80’s when hurt last season.

Bray has been working with pitching coach Steve McCatty to try to rid himself of the bad habits that cropped up last year when injured. He always threw from a high three-quarters arm slot, but has been throwing with his arm above his head.

Fernando Abad, who also signed a minor league deal with a big league camp invite, has emerged as the leading candidate to serve as the Nationals’ second left-hander in the bullpen, if they choose to add another arm to join Zach Duke.