BOSTON -- The D-backs on Wednesday signed 15 of the 50 players selected in the 2010 First-Year Player Draft.

The players signed include Derek Eitel (17th round) and Gregory Robinson (32); catchers Kawika Emsley-Pai (10) and Andrew Whittington (33); infielders Zachary Walters (9), Jimmy Comerota (18), Yazy Arbelo (26), Tom Belza (43) and Eric Groff (44); and outfielders Westley Moss (16), Adam Eaton (19), Michael Hur (20), Justin Hilt (36), Christopher Jarrett (42) and Javan Williams (45).

Robinson, Emsley-Pai, Arbelo, Comerota, Walters, Belza, Hilt and Moss were assigned to short-season Class A Yakima.

Eitel, Whittington, Groff, Eaton, Jarrett and Williams were assigned to advanced Rookie-level Missoula.

Hur is still awaiting assignment.

Qualls confident he can turn things around

BOSTON -- No one is more perplexed by the struggles of Chad Qualls this year than the right-hander himself.

"What we've seen lately is definitely not what I've portrayed in my career," the Arizona reliever said. "I feel like I'm really close. I need to just get more consistent being down in the zone."

While he works on trying to get to that point, D-backs manager A.J. Hinch plans to use Aaron Heilman to close out games rather than Qualls, a move he announced prior to Tuesday's game.

Qualls has struggled throughout the season, compiling a 1-3 record and an 8.46 ERA in 28 games. The right-hander has blown four saves in 16 opportunities.

"It's frustrating for me," Qualls said. "I know I'm better than this. If this is a step back in order for me to go forward in my career, then that's what I have to do."

Qualls' signature pitch is his sinker, and regaining his effectiveness with it is the key for him at this point.

"Sometimes the ball runs on me when I get the ball up in the zone, and that's the reason why a lot of guys are getting the ball in the air," Qualls said. "I need to go back to getting the ground balls."

Having confidence when you're struggling is tough, but Qualls is banking on the success he's had in the past to keep his spirits up.

"It's tough. I mean, I've never had to go through this long of a stint like this in my career," he said. "For the most part, it's been fairly easy for me to go out there and get the job done. It's hard to deal with when you've never had to go through it before. I've shown in my past that I'm too good of a pitcher for this to carry on."

Webb pleased with Fenway bullpen session

BOSTON -- After throwing 25 pitches off a mound Wednesday, D-backs right-hander Brandon Webb was not pleased.

After 75 pitches, though, he was all smiles.

"Those first ones, I was a little discouraged," Webb said. "For some reason, I don't even know what it was, I was still kind of short and cutting off in front and keeping it short in back. But the second set, I was just trying to keep everything long and really stretch out and reach out front, and it felt great. I went from being kind of discouraged to it went real good and I was real happy with it."

There has not been a lot for Webb to feel good about since undergoing right shoulder surgery last August. He started throwing off a mound in January, but after struggling during a bullpen session March 4, he had not thrown off a mound until this past weekend.

Webb is still trying to get comfortable with his mechanics again. He discovered in April that his arm slot was higher than it had been in the past, and that was one of the things holding him back.

On Wednesday, he did not use a full windup the entire time -- more of a step with his right foot against the rubber and throw -- but still he continues to move forward in his bid to return to action. Webb has not pitched in a game since Opening Day of last year.

Webb will play catch the next couple of days before getting back on the mound for another bullpen session this weekend while the club is in Detroit.

"I'm not even trying to throw hard, but it's coming out way better, so I feel like I've got a lot more in there, so that's encouraging, too," Webb said. "Hopefully it won't take me long, and once I get [the mechanics] down, it should go quickly."

Demel happy to be in big leagues

BOSTON -- Sam Demel doesn't know what his specific role will be, and the newly acquired reliever could not care less.

"I'm just here to throw when they want me to," the right-hander said. "I'm more than willing to do anything. Roles have to be earned, they aren't given."

The D-backs acquired Demel on Tuesday from the A's in exchange for outfielder Conor Jackson. The 24-year-old was 2-0 with a 1.26 ERA and six saves in 22 games for Triple-A Sacramento at the time of the deal.

Demel did not have to wait long to make his Major League debut, as he was summoned to start the eighth inning in Wednesday night's 6-2 loss to the Red Sox.

Demel retired the three batters he faced -- J.D. Drew, Adrian Beltre and Mike Cameron -- in order.

"I thought he looked good," D-backs manager A.J. Hinch said. "That's about as good as it gets coming into Fenway. I thought he showed a lot of composure and poise. His stuff was good."

Demel's Sacramento team was playing host to Reno, Arizona's Triple-A affiliate, when the trade went down. Demel got the news around 8:15 a.m. PT on Tuesday and was still trying to have it sink in when he showed up at Fenway Park on Wednesday.

"I was just waiting in Sacramento and putting up good numbers and hoping I could get up to Oakland," he said. "Any opportunity you can get is amazing."

Demel added a cut fastball to his repertoire this year to go with a change and slider.

"I just attack the zone," he said when asked to describe his pitching style. "I just go out there and attack and try to get guys to get themselves out."

To make room for Demel on the roster, the D-backs optioned right-hander Cesar Valdez to Reno. The right-hander began the year there as a starter, and after a pair of starts at the big league level, he was moved to the bullpen. Hinch said Valdez would be stretched back out in three- to five-inning stints with Reno.