Even on the day of their second spring training game, the Nationals possess very few unknowns about the composition of their opening day roster. The biggest question concerns the final spot or two in the bullpen, and the biggest factor in answering that may be the performance of lefty Bill Bray.

Bray, in camp on a minor league contract, has been one of the best left-on-left relievers in baseball in recent seasons. He made his spring debut yesterday, his first appearance after missing almost all of last season with a groin injury. Bray allowed two runs, one earned, on three hits.

“Good and bad,” Bray said. “From the perspective of where I came from last year, it was good.”

The positive came from how he felt. He was strong – he hit 90 and 91 miles per hour with his fastball, which is in line with his career average. Last year, as the groin injury led to back pain, and back pain wrecked havoc on his mechanics, his velocity dipped into the high 80s.

The negative came from the results, and the lingering defect in his mechanics. Bray is still trying to rid himself of the bad habit that cropped up last year. He has always thrown from a high three-quarters arm slot. “Right now,” Bray said, “I’m right over the top.”

“That’s a working process,” pitching coach Steve McCatty said. “We keep doing it. It’s something that became a bad habit last year. It’s really hard to break. He’s doing his best to make the club, so in the games we don’t stress on it. I told him, ‘Just relax. Quit thinking about it.’ And we continue to work on it. The ball was coming out of his hand. The velocity was better than last year. He’s healthy. But it’s not easy to get that feel back.”

If Bray can prove himself healthy and effective in the next five weeks, he could give the Nationals an element they would not otherwise have – a shutdown lefty out of the bullpen. In his career, Bray has held lefties to a .218 average. Zach Duke, pegged a long reliever, is the only left-handed reliever the Nationals currently have signed to a major league deal.

If not Bray, the Nationals could simply go with Henry Rodriguez or, if he doesn’t become a starter, Christian Garcia with their final bullpen spot. There are also two sleepers to keep in mind: The Nationals have been impressed with Fernando Abad, who had a 5.09 ERA with the Astros last year but has held lefties to a .699 OPS in his career. Yesterday, Abad pitched a scoreless inning against the Mets, which ended with a strikeout on a wicked curveball. Brandon Mann, who spent the last two years in Japan, has also opened some eyes. Mann is a true longshot – at 28, he has never pitched above Class High-A in American pro ball.

One last note from the morning: Davey Johnson said Matt Purke, coming off winter shoulder surgery, will not pitch in any games until May. The Nationals signed Purke to a major league deal out of the 2011 draft worth $4.15 million, but he made only three starts last year because of shoulder problems.