PHOENIX -- Aaron Heilman threw another bullpen session Thursday and the D-backs reliever could be close to returning to action.

Heilman has been out since April 14 due to tendinitis in his right shoulder.

Heilman said that he expects to face hitters in a simulated game at Chase Field on Sunday and then he should be ready to be activated.

"I don't think so," Heilman said when asked if he thought he needed a Minor League rehab assignment. "I feel good. My command was good today, everything is pretty much there."

Young keeps grinding to break free of slump

PHOENIX -- When the D-backs returned from their recent road trip, manager Kirk Gibson asked outfielder Chris Young if he wanted to take a day off.

Young, in the midst of a 1-for-21 slump, politely declined.

That did not surprise hitting coach Don Baylor.

"He continued to do his work, without question," Baylor said. "If he's hot or cold, whatever, he does his work every day."

In the three-game series with the Phillies, Young was 3-for-12 with three homers, two of which came in Wednesday's finale.

Typical of Young, though, he was out for early hitting Thursday.

"He was out here working early today and he had a great session," Baylor said. "He's back to hitting those line drives so his average will go up."

The hard work paid off in the D-backs' 11-2 win over the Cubs on Thursday. Young tallied two hits in the seven-run first inning, including a two-run single, and finished the game 3-for-5, lifting his average from .216 to .235.

Curveball emerges as vital pitch for Vasquez

PHOENIX -- Esmerling Vasquez looks like a different pitcher this year, and a change in his repertoire could be a big reason why.

The D-backs reliever has pitched well since being recalled from Triple-A Reno earlier this month and has become manager Kirk Gibson's primary seventh-inning setup man.

Where in the past Vasquez threw a slider to go with his fastball and changeup, this year he is sporting a curveball.

"Last year I didn't feel too confident with the slider," Vasquez said.

While pitching in winter ball, Vasquez threw a few curveballs and was encouraged by Yankees right-hander Ivan Nova to throw it more. Soon he realized that he had better command of the curve than he did with the slider and stuck with it this spring and so far this season.

"I think it's a good pitch for me now," Vasquez said. "I can throw it for strikes."

Vasquez has a 2.35 ERA in seven games.

D-backs infielder Wilson able pitch in pinch

PHOENIX -- Josh Wilson had his contract purchased this past week to provide protection at shortstop with Willie Bloomquist heading to the disabled list.

But the D-backs veteran said he is also able to pitch if need be.

The D-backs saw that firsthand in 2009, when Wilson pitched an inning for the D-backs on May 11 and then pitched an inning against them June 7 after he was picked up by the Padres.

Wilson hit 92 mph during one of those appearances and said that he's added a cut fastball to his bag of tricks to go along with a curve and changeup.

"I've never had any arm problems," Wilson said. "Throwing doesn't bother me."

D-backs manager Kirk Gibson was asked about using Wilson in a blowout game.

"That's not something I want to think about," Gibson said. "I look at him more as insurance at shortstop. It's not something I'm expecting to happen."