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7/28/2014 10:44 P.M. ET

Pirates perplexed by Alvarez's throwing woes

SAN FRANCISCO -- The subject has become an uncomfortable one for Clint Hurdle. Whenever he is again asked about Pedro Alvarez's throwing issues, the Pirates manager answers listlessly -- as if he didn't really have an answer.

How could he? To try to explain how Alvarez has become a frequent threat to fans sitting behind first base, he'd have to get into the third baseman's head. Which, by the way, Hurdle has tried.

The only thing the manager has been able to do, however, is continue to express admiration for Alvarez's work ethic and to support him -- and to remove him for defensive purposes late in games the Bucs lead.

Alvarez has 23 errors -- nearly twice as many as any other third baseman in the National League (Arizona's Martin Prado has 12) -- and 21 of them have come on throws. Routine throws -- since he has retained the uncanny ability to finish off tough plays with strong, accurate throws.

"We continue to see great instincts, reflexes [but] every once in a while, there's a play where he decelerates, and it kind of throws off the rhythm and quite possibly the throwing slot," Hurdle said. "What we continue to try to get him to do is to keep moving. To keep that steady flow of energy, without any 'switches,' on and off."

When he tied for the NL lead with 36 homers last season, Alvarez was in the conversation with the prime Ryan Howard, his development being compared to the strikeout-prone but dangerous Philadelphia first baseman.

Now, he is on the verge of being compared to Steve Sax and Chuck Knoblauch, a pair of infielders who developed a harrowing inability to throw to first base.

Alvarez hit his most recent home run July 11, his 15th. Since that blow, he has committed five errors.

Cole hurls five scoreless innings in rehab start

SAN FRANCISCO -- Gerrit Cole's first rehab start for Triple-A Indianapolis won't make Pirates fans any more patient waiting for his return.

Taking the mound for the Indians on Monday night in Rochester, Cole blanked the Red Wings for five innings on five hits. He had three walks and struck out seven, delivering 50 of his 81 pitches for strikes.

The agenda for Cole, on the DL with a sore lat since July 9, calls for him to make two rehab starts for the Triple-A club and stretch out close to 100 pitches in the second turn.

On regular schedule, that second rehab start would happen Saturday. That would put Cole on track to rejoin the Bucs' rotation Aug. 8, in the opener of a three-game series against the Padres in PNC Park.

Snider adapting well to pinch-hitting role

SAN FRANCISCO -- History will determine the significance of Travis Snider's latest pinch-hit heroics. The next two months will give perspective to his game-tying, two-run home run in the sixth inning Sunday in Denver.

Unquestionably, though, Snider came off the bench to wake up a stodgy group of Pirates on the verge of being swept out of Coors Field and point them toward a 7-5 victory. It was yet another example of how Snider, a onetime No. 1 Draft choice, has taken to a supporting role at the still-young age of 26.

Pittsburgh pinch-hitters lead the National League in numerous categories, including hits (42) and RBIs (27, tied with the Rockies). The loudest bat in that niche has been swung by Snider, the individual league leader with 12 pinch-hits.

Pinch-hitting specialists are a baseball staple, from Lenny Harris to Manny Mota to Jerry Lynch. Ordinarily, they are veterans in a latter phase of their careers. It is extremely rare to find someone specialize in the difficult craft at 26 -- because at that young age they tend to fight, not accept, it.

"You've got to buy into that role," said manager Clint Hurdle. "The biggest step forward is the mindset. 'I should be doing this. ... I didn't get to do that.' You've got to let go of where you were and embrace where you are."

During Spring Training, Snider talked very candidly of just keeping right field warm for Gregory Polanco, recalling that at one time he "was the big prospect." The baseball line always moves along. Snider had no qualms accepting his current place in that line.

In so doing, the popular Twitter personality has also morphed from Lunch Box Hero to Batter's Box Hero.

First number, last word

.769 The combined on-base percentage of Pirates catchers Russell Martin and Chris Stewart in the three-game series last weekend in Colorado.

"It hasn't cooled off for me by any means. ... There's a large poker game going. I think we are looking at a couple specific areas." -- Hurdle, assessing the trade market with three days to go to Thursday night's non-waiver Trade Deadline.

Worth noting

Clint Barmes (strained left groin) stepped up his rehab to fielding grounders hit to him and participating in regular batting practice prior to Monday night's game against the Giants.

• The string of left-handers facing the Pirates -- San Francisco's Madison Bumgarner was the eighth in 10 games since the All-Star break -- keeps benched one of the team's hottest hitters. Ike Davis, the lefty-hitting first baseman, was 6-for-14 (.429) with two homers and five RBIs since the break, much of it coming off the bench.

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.