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7/22/2013 11:43 P.M. ET

Grilli departs in ninth inning with forearm discomfort

WASHINGTON -- The sight of Jason Grilli, their dedicated and effective All-Star closer, walking off the Nationals Park mound in pain cast a pall over the Pirates' 6-5 victory Monday night.

The mood in the visitors' clubhouse definitely was closer to wake than to celebration.

Two strikes from what would have been his 31st save, Grilli threw one pitch to pinch-hitter Steve Lombardozzi, grimaced, motioned to the Pirates' third-base dugout for trainer Todd Tomczyk and minutes later walked off the field clutching his right elbow.

"We'll wait and see where it all goes, but right now, it's right forearm discomfort," said Pirates manager Clint Hurdle, cautioning reporters. "And that's all I've got, so no sense asking me anymore about it. We're not running him out of here. We'll see how he feels tomorrow."

"Praying everything is all right," said Andrew McCutchen, whose pair of two-run homers had fueled the victory.

McCutchen lockers next to Grilli, who was sitting with a towel wrapped around his right forearm, staring down and into his own locker. McCutchen spoke through a forced smile, and when reporters receded, walked up to Grilli and draped an arm around his shoulders.

In the event of Grilli's absence, closing duties would fall to fellow All-Star Mark Melancon, who has excelled as the Pirates' setup reliever and served as the man at the end of Houston's bullpen in 2011.

No discomfort for Walker during rehab stint

WASHINGTON -- Neil Walker got to bat from both sides of the plate, got a couple of hits and participated in a couple of double plays. But the best thing to happen to Walker during his rehab weekend at Triple-A Indianapolis was swinging and missing.

Getting fooled on pitches rarely felt as good -- because Walker couldn't feel any discomfort in the right oblique area that put him on the disabled list on June 9.

"I swung through a couple pitches with hard swings and finished [the swings] the same way as when I strained it," Walker said. "And it didn't give me any issues -- no pinching, or tightness, or cramping. That was a tell-tale sign for me."

The tell-tale signs for the Pirates will be how Walker reacts to his full-boar Monday workout at Nationals Park, and how doctors check him out. That was one reason the second baseman wasn't activated for Monday night's game. Another was manager Clint Hurdle's reluctance anyway to have him play a fourth straight day with an injury that ordinarily has been a higher, longer obstacle.

"I think we pushed him dramatically, playing in three straight [with the Indians]. I thought that was a big push," Hurdle said. "The minimum time somebody being down with [an oblique] will be this, if we can pull this off. It'll be the least amount of time I've ever seen a player miss with an oblique."

If Walker passes his tests, he will be activated and returned to the lineup for Tuesday's game.

Since the start of the 2012 season, the Pirates are 108-86 when Walker is in the starting lineup, and 28-36 when he is not. If Walker is back at second base, Jordy Mercer presumably will return to the other side of the bag -- although veteran Clint Barmes has batted .357 in nine consecutive starts at shortstop afforded by Walker's absence.

Worth noting

• Pedro Alvarez started Monday night's game without a hit in his previous four games. His only hitless rut of the season came in the first week, when he was hitless in seven straight [including six starts] from April 4-10. Alvarez was 0-for-24 in that stretch.

• Bullpen excellence is not exactly a one-year phenomenon in Pittsburgh. Even though many of the faces have changed, since the start of the 2012 season the Pirates are 119-2 when taking a lead into the ninth.

• Entering Monday's tilt, Andrew McCutchen had capitalized on Nationals pitching for a .533 average (16-for-30) in his last eight games in Washington.

First number, last word

1,000 -- Career games reached by Barmes with his Monday start at shortstop; teammate Russell Martin reached the same milestone on July 14.

"The hitting coach position is the most volatile position now in Major League Baseball. I know it's a very challenging job, and it takes time to develop trust, to get players to buy in." -- Hurdle, a former hitting coach himself, on the revolving door through which the Nationals' Rick Eckstein spun out and Rick Schu spun in on Monday.

Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. This story was not subject to the approval of Major League Baseball or its clubs.