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5/3/2013 11:52 P.M. ET

Walker lands on disabled list with hand injury

PITTSBURGH -- After carrying Neil Walker all week despite his inability to play with a laceration on his right hand, the Pirates on Friday belatedly placed him on the 15-day disabled list.

Walker, whose injury status is retroactive to April 27 and can be activated on May 12, was replaced by infielder Jordy Mercer, recalled from Triple-A Indianapolis.

Walker was injured trying to break up a double play last Friday in St. Louis. He had reported daily progress in his workouts, and had an extensive workout on Friday afternoon at PNC Park, prior to the decision to place him on the DL.

The move, oddly, was influenced by an injury to another player which furthered weakened the Bucs' bench: Jose Tabata is limited by a tweak of his left hamstring, and his availability will be limited through the weekend series with the Nationals.

"You hate to throw him on the DL that quick, without giving him some down time to see what's there," manager Clint Hurdle said of Tabata. "We'll see if we can carry him through the weekend. Then we may have to do something. Tuesday is probably the day we'll have to make that decision."

Mercer was hitting .333 with 19 RBIs in 26 games with the Indians. He spent much of the 2012 season with the Pirates, often used as a defensive replacement while totaling only 62 at-bats in 42 games.

Grilli named Delivery Man Award winner for April

Jason Grilli's first season as a closer could hardly have gotten off to a better start, as the Pirates right-hander was selected on Friday as the winner of the Major League Baseball Delivery Man of the Month Award for April. The award recognizes the most outstanding relief pitcher of the month, as voted on by a panel from MLB.

In 12 April appearances, Grilli converted all 10 of his save opportunities to tie for the Major League lead, posting a 0.82 ERA, 0.82 WHIP and .132 opponents' average. He struck out 17 while walking four and giving up five hits.

In his first 10 Major League seasons, Grilli totaled five saves. The Pirates handed the 36-year-old the reins to the closer's job this year when they dealt Joel Hanrahan to the Red Sox. He responded by becoming the second Pirates pitcher to save 10 games in April, joining Mike Williams, who did so in 2002.

Grilli, who recorded saves on back-to-back days four times, is the third Pirates hurler to win a Delivery Man of the Month Award, joining Hanrahan (June 2011) and Jose Mesa (April 2005).

Grilli has shown no signs of letting up in May, pitching a scoreless inning for his 11th save on Wednesday against the Brewers to drop his ERA to 0.75.

Karstens to continue rehab; Morton has setback

PITTSBURGH -- Pirates right-hander Jeff Karstens will soon depart for Florida to continue his recovery from shoulder inflammation, and is on schedule to take right-hander Charlie Morton's place on Triple-A Indianapolis' rehab list when the veteran rejoins the Pirates.

But Morton, about to hit the stretch on his comeback from Tommy John surgery, instead hit a bump in the road Friday night.

The right-hander had to leave his Indianapolis start against Lehigh Valley after three innings with tightness in his right shoulder. Morton was scheduled to go six innings or throw 90 pitches in the fourth of his five rehab starts. Instead, he was removed after 49 pitches, without allowing a hit.

Morton is returning to Pittsburgh for further medical evaluation. He was due for one other Minor League outing and had been penciled by manager Clint Hurdle into the Bucs' rotation for a May 14 start.

As for Karstens, he threw a two-inning simulated game Friday afternoon at PNC Park, and said everything "felt good" after he worked on all of his pitches.

Karstens is tentatively scheduled to fly on Monday to Florida, with his first two outings scheduled for Wednesday in extended spring camp, and for May 13 with Class A Bradenton.

That timetable puts the veteran righty on target to possibly step up to Indianapolis for the ensuing rehab start.

Worth noting

• With newcomer Jordy Mercer taking his place at second base Friday, Brandon Inge made his first career start in right field, a spot he last played as a reserve in 2004. Inge hadn't started anywhere in the outfield since a dozen starts in center for the '08 Tigers.

• Gaby Sanchez started Friday night's game tied for the team lead with 16 RBIs. Compared to co-leader Andrew McCutchen's 101 at-bats, Sanchez's RBIs had come in 49 at-bats. After the Pirates acquired him from Miami at the 2012 Trade Deadline, Sanchez drove in 13 runs in 116 at-bats.

• Former Pirates infielder Casey McGehee is tearing it up in Japan, leading the league with a. 396 average, and has an OPS of 1.113.

First number, last word

86-1: Pirates' record, since the start of the 2012 season, when they take a lead into the ninth inning.

"He's a work in progress, but the first-month results were very good. If he was a stock, you'd be very happy with your return after the month of April." -- Hurdle, on Starling Marte's start to his first full Major League season

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. Andrew Simon is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.