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5/5/2013 7:06 P.M. ET

Martin, who wears No. 55, has thrived on 5/5

PITTSBURGH -- If Russell Martin goes 5-for-5 in Sunday's game against the Nationals, don't be surprised. Just call it predestined.

May 5 ... 5/5 ... Cinco de Mayo -- or, as they say in Martin's French-Canadian home, Cinq Mai -- is his day.

Martin has worn No. 55 throughout his career. He made his Major League debut on May 5, 2006 -- totally coincidentally -- and went 2-for-4 with a pair of RBIs for the Dodgers against the Brewers.

He went into Sunday's game as a lifetime .385 (10-for-26) hitter on the date, with one homer and -- what else? -- five RBIs. In Sunday's 6-2 loss to the Nationals, he went 1-for-3 with an RBI single and also made a sliding catch at third base.

But here is the clincher:

In making out his lineup against Washington left-hander Gio Gonzalez, Pirates manager Clint Hurdle gave Martin his second start of the season at third base -- the "5" position on your scorecard.

Hurdle also listed Martin in the five-hole.

"Should be a great day," Martin said with a wink before taking the field.

Tightness not serious, Morton set to play catch

PITTSBURGH -- Charlie Morton and the Pirates got good news from exams of the right-hander's shoulder after he left his most recent rehab start with tightness in the joint.

Morton's condition was diagnosed as tightness in the back of the shoulder, and he is tentatively scheduled to be back on the mound by next weekend.

"It's definitely good news," manager Clint Hurdle said. "Nothing more serious. We'll slow him down a bit, and hopefully resume his rehab shortly."

Morton is scheduled to play some flat-ground catch on Tuesday at PNC Park, then travel with the club for next weekend's series in New York with the Mets and throw a bullpen session in Citi Field.

"Following that, we hope to resume his rehab," said Hurdle, who qualified any perceptions that the development is a setback to Morton's comeback from Tommy John surgery.

"It isn't. Because you don't know ... you just keep moving forward and deal with what you have to deal with," Hurdle said. "It's the next challenge in his rehab. He was alarmed by what he felt, and it was proper to shut him down -- but he understands it's just something he has to push through."

Worth noting

• The Pirates' overdependence on homers last season was perceived as making them prone to scoring slumps, but Hurdle was not concerned with the fact the Bucs started play Sunday having scored 18 of their last 21 runs on long balls.

"Just the way it comes. We try to build innings, see pitches, run up pitch counts. We've seen some pitches left up in the zone, and we're putting good swings on them," Hurdle said.

• Francisco Liriano made his final rehab start Sunday for Triple-A Indianapolis, and will next take the mound for the Pirates on Saturday in New York against the Mets. The lefty had been sharp in his first four rehab starts -- three walks and 27 strikeouts in 16 2/3 innings -- but Hurdle watches such numbers through the Minor League prism.

"Has his command been solid? Yes," the manager said. "But you have to keep in mind the quality of hitters from the top to the bottom of the lineup. Are they swinging at the same pitches as they will in the Majors? We don't know."

First number, last word

10-8: The Pirates' record in Interleague games last season, tied with the Reds for best in the National League.

"It'll be more of a challenge than it's been in the past, when the schedule was more concentrated. Time will tell. We feel best suited with the club we have, and we do have a DH in the house." -- Hurdle, who in the past would adjust his roster with the addition of an extra hitter for Interleague games, on the revised schedule which has Interleague games dispersed throughout the 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. This story was not subject to the approval of Major League Baseball or its clubs.