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5/3/2014 8:05 P.M. ET

Lambo rebounding from tough spring in Minors

PITTSBURGH -- The hottest left-handed hitter in Triple-A Indianapolis the past two weeks? The outfielder who has raked .410 with two homers and 12 RBIs in his past 10 games?

Say "hello again" to Andrew Lambo.

Maybe not who you expected? Oh, top prospect Gregory Polanco is still at it, batting .385 with his own two home runs and nine RBIs in his past 10 games.

However, if in need of some lefty power, clearly Lambo, with significant Major League experience late last season, would get a call prior to Polanco. After a rough start to his season, most likely from a funk upon being optioned at the end of a frustrating Spring Training, Lambo has picked it up impressively.

He may have also gotten a lift from the Bucs' scratching the first-base experiment -- once Ike Davis was acquired via trade -- and returning him to regular outfield play.

"These last two weeks have been his best," said Pirates manager Clint Hurdle, who regularly consults with Indianapolis manager Dean Treanor. "He's gotten some momentum. The bat has come more into play; he's becoming more offensive while continuing to work on his overall game."

As for Lambo's assignment to get over his 4-for-42 time in the Major League camp, Hurdle referred to it as a "challenge."

"Challenges are what make life interesting, and overcoming them makes life meaningful," Hurdle said.

Pirates add Hughes, Mazzaro to bullpen mix

PITTSBURGH -- The Pirates' bullpen got a shakeup prior to Saturday night's game against Toronto at PNC Park.

Relievers Jared Hughes and Vin Mazzaro were called up from Indianapolis, taking the roster spots of Brandon Cumpton, optioned to the Triple-A club, and Stolmy Pimentel, placed on the 15-day disabled list with right shoulder inflammation.

For Hughes, this marks his third stint -- within two weeks -- with the big league club. Mazzaro's contract had to be selected from Indianapolis, to where he had been outrighted after passing through waivers at the end of Spring Training.

Cumpton had another strong start in the nightcap of Thursday's doubleheader in Baltimore, but the Bucs needed his rotation spot for whoever will start Monday night against San Francisco. That decision has not yet been made, but it will likely come down to one of two lefties -- Jeff Locke or Wandy Rodriguez [right knee inflammation], eligible to come off the DL on Monday.

Pimentel has been used extremely sparingly, with six appearances despite having spent all of the season's first month in the Bucs' bullpen. He has allowed a run in four of his last five appearances.

Mazzaro was pretty close to perfect in six appearances with the Indians, going 1-0 with two saves and not allowing an earned run in 10 2/3 innings.

Hughes went 1-0 with four saves and a 0.00 ERA in six Triple-A appearances between two scoreless outings for the Bucs.

Walker's plan vs. Dickey: keep him guessing

PITTSBURGH -- A couple of hours prior to stepping up against Toronto right-hander R.A. Dickey on Saturday night, Neil Walker still did not know which batter's box he would be stepping into -- left or right.

Would the switch-hitter buy into the theory/myth that knuckleball pitchers are easier to read by same-side batters?

"We were just talking about that, and Neil said it would be a game-time decision," Pirates batting coach Jeff Branson said on his way to the field for pregame batting practice. "Neil says he always batted right-handed against knuckleball pitchers in the Minors. He felt comfortable."

Walker was not in the lineup the most recent time the Pirates had faced Dickey, on Sept. 27, 2012, when with the Mets he notched his 20th win that season.

Walker went so far as to indicate to Branson that he would take swings from both sides when on-deck, then make his call on the way to the plate.

Walker was back in the lineup's two-hole, from where he had gone 3-for-4 in the Bucs' 6-5 walk-off win Friday night.

First number, last word

4: Pirates walk-off wins, out of their first seven victories of the season at PNC Park.

"I'm getting real good at it … get the belt out, take the shoes off, put your stuff on the belt." -- Hughes, returning from Indianapolis to the Pirates' clubhouse for the third time since April 21, on going through airport security as a "civilian," versus the convenience of traveling with the big league club.

Worth noting

• In the 55 years of divisional play, Starling Marte on Friday night became only the fourth Pirates player to end a four-hit night with a walk-off homer. He matched the feats of Freddy Sanchez (June 29, 2006, vs. the White Sox), Johnny Ray (May 30, 1982, vs. the Giants) and Rennie Stennett (July 20, 1973, vs. the Padres).

• Milwaukee is the only NL Central team with a winning record, helped by the fact the Brewers are 15-0 when they outhit the opposition. The Bucs were 9-3 under those circumstances entering Saturday night's game.

• The Pirates' and Blue Jays' mutual dependence on the long ball makes this Interleague series at PNC Park intriguing. When hitting fewer than two home runs, the Bucs were 5-17 and the Jays 7-12 through Friday.

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.