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6/27/2013 12:01 A.M. ET

Getting closer, Pineda's next start set for Sunday

NEW YORK -- Michael Pineda's next Minor League rehabilitation outing will come on Sunday for Double-A Trenton at Binghamton, Yankees general manager Brian Cashman said.

Pineda threw six scoreless innings on Tuesday for Trenton against Erie, throwing 78 pitches. He allowed two hits and two walks while striking out four.

"I was watching the tape, and you can see the movement on his fastball," Yankees manager Joe Girardi said. "His slider looked pretty good, his changeup looked pretty good."

Pineda, 24, is coming back from right labrum surgery following an injury sustained last spring. In three official Minor League starts, two with Class A Advanced Tampa, Pineda has allowed three runs (one earned) in 14 1/3 combined innings, allowing nine hits with four walks and 11 strikeouts.

A 2011 American League All-Star with Seattle, Pineda has not yet pitched for the Yankees at the big league level, but his debut finally appears to be in sight.

"I'm very excited," Pineda said after Tuesday's start. "I've never pitched at Yankee Stadium. I'm working hard and will be ready to pitch there."

Joba's struggles continue in outing vs. Rangers

NEW YORK -- Joba Chamberlain kept his head down as he trudged toward the first-base dugout, and though he said that he didn't really notice the boos pouring out of Yankee Stadium's grandstands, the reliever also wasn't surprised by them.

Chamberlain turned in another ineffective relief outing for the Yankees on Wednesday, serving up a two-run homer to Nelson Cruz among four hits he permitted while recording two outs in the seventh inning of New York's 8-5 loss to the Rangers.

In Chamberlain's last seven appearances, he has served up four homers, permitting a total of 14 hits and nine earned runs over 6 2/3 innings (12.15 ERA).

"Obviously, I would boo me, too. I'm terrible," Chamberlain said. "There's no getting around it. Obviously, you come and spend money and you want to see someone do their job. It's one of those things where if you don't do your job, you expect to get booed. They have a right to. You can't get mad at them."

Yankees manager Joe Girardi has already shifted Chamberlain to lower-leverage situations, bringing him into games where the club is trailing for six straight appearances. Girardi said that Chamberlain is making mistakes in the middle of the plate and getting hammered for it.

"Somehow we have to find a way to get him going. That's the bottom line," Girardi said. "This guy needs to help us. To me, his stuff is too good not to help us, but right now, he's making mistakes."

Chamberlain has a 6.38 ERA in 19 appearances this season. He said that he would watch video to see if there is a mechanical adjustment that needs to be made, but noted that his velocity has seemed fine, so improving fastball command is his primary goal.

"Obviously, it's frustrating letting the team down. That's the worst part," Chamberlain said. "I know I [stink] right now. There's no getting around it. You've got to figure out what you can do to make it better."

Nunez set to begin rehab assignment Thursday

NEW YORK -- Yankees shortstop Eduardo Nunez was scheduled to begin a Minor League rehabilitation assignment on Wednesday for Class A Advanced Tampa in the Florida State League, but after a rainout, Nunez is expected to play in his first game for Tampa on Thursday.

Nunez, 26, has not played in a game since May 5 because of a left oblique strain that he subsequently re-injured while rehabbing in Tampa, Fla., and is on New York's 60-day disabled list.

Nunez started the season as the Yankees' everyday shortstop with Derek Jeter on the disabled list but batted just .200 (16-for-80) with no home runs and four RBIs in 27 games.

"We expected Derek, and then that changed," Yankees manager Joe Girardi said. "Nunie went down, and we've had a number of guys who have played shortstop since then.

"[The plan has] changed a little bit, but I don't really think it changes what your goal is. Your goal is always the same; you just end up making a lot more moves than you anticipated, and looking for players that can help you."

Bombers bits

• Wednesday marks Jeter's 39th birthday. This is the second time in Jeter's career that he has been on the disabled list for his birthday (also 2011) and he will not play a game on his birthday for the sixth time since 1996.

• Girardi won his 599th career game as a manager on Tuesday, and he will become the 16th current manager to reach the 600-win plateau with the Yankees' next victory. 521 of Girardi's 599 victories have come in pinstripes.

• On this date in 1939, the Yankees played their first night game at Philadelphia's Shibe Park, losing, 3-2, to the Athletics.

Bryan Hoch is a reporter for MLB.com. Follow him on Twitter @bryanhoch and read his MLBlog, Bombers Beat. This story was not subject to the approval of Major League Baseball or its clubs.