The biggest surprise of the Pirates' first half might be starting pitcher Jeff Locke, who entered the weekend with the team lead in wins (8) and the second lowest ERA in the National League (2.12).
But Pirates fans don't have to think back too far to remember another young pitcher who pitched his way into the spotlight with an uncharacteristic first half.
James McDonald went 9-3 with a 2.37 ERA in the first half of 2012 before coming unglued after the All-Star break. In the second half, he went 3-5 with an ERA of 7.52.
McDonald and manager Clint Hurdle said they learned lessons in the ups and downs of the 2012 season that could come in handy if and when Locke faces adversity.
"Don't try to do too much," McDonald said. "Don't try to put too much on your shoulder. Just remember you've got other guys behind you that can contribute, too."
Many sabermetrically minded pundits predict Locke is due for a regression -- and that could come at any time. They point to his .233 batting average on balls in play. If that rises closer to the league average (.293), his ERA will climb with it.
Those advanced projections suggest Locke's ERA should be closer to the high 3s.
Hurdle, who is not big on expectations and projections, said he does not anticipate a big drop off in Locke. He also does not have much advice for Locke to maintain success where McDonald could not. But if Locke's season starts to slide, that's where McDonald's struggles could come in handy.
"I think we've got some experience and some probably useful information if his second half turns into what J-Mac's did," Hurdle said. "That's about all I got right there because I'm not anticipating that."
McDonald said the key for Locke is to be as consistent as possible after the All-Star break.
"Just keep doing what you do," he said. "Keep bringing what you bring to the team, which is a lot. Don't get out of your shell and do something new, become a new guy in the second half. Just be the same Jeff Locke you've been all year.
"He's a real stubborn guy. He'll be fine."
If anything, Locke said that mentality has allowed him to experience the success he has already had. Being named to the opening day rotation was a vote of confidence for Locke, who was pitching in the past like he was in survival mode.
"I've been telling everybody this since this run started, I just try to do everything the same every time out," he said.
Sabermetric rattling along the stat lines
For the third consecutive season, the Pirates have been catapulted to first-half success by a strong pitching staff.
But this is the first of those three years that strong pitching has been emboldened -- perhaps enabled -- by quality defense.
The Pirates entered the weekend ranked 23rd in the majors with a .982 fielding percentage -- the exact fielding percentage with which they finished the 2012 and '11 seasons. But they rank among the league's best in many advanced defensive metrics, showing drastic improvement from the prior two seasons. As a result, they are turning more balls in play into outs, which in turn bolsters the performances of the pitching staff.
The Pirates rank sixth in the major leagues -- and third in the NL -- in ultimate zone rating (13.4), a metric that attempts to quantify how many runs a player -- or in this case a team -- saves or allows because of his defense. And they trail only the Milwaukee Brewers in the major leagues in out of zone rating (294), a measure of how many outs a player or team makes out of a defensive zone.
The speedy Starling Marte and Andrew McCutchen help bolster those stats by covering a lot of ground in PNC Park's spacious outfield. That ability to patrol the ballpark allows the Pirates' right fielder to cheat a bit closer to the line.
In 2012, the Pirates were 16th in the majors in UZR and eighth in OOZ. In 2011, they were 24th in UZR and ninth in OOZ.
Hurdle said the "defensive creativity" the Pirates are using this season has also had an impact. Specifically, the Pirates have utilized the shift more. And Russell Martin has been more aggressive "backpicking," or picking off runners who take aggressive secondary leads, than his predecessors.
Martin's addition has given the Pirates a new dimension behind the plate, too, especially in controlling the running game. Entering the weekend, he had caught 18 potential base-stealers, one shy of the team total in 2012. He is catching 46 percent of would-be thieves while Rod Barajas and Michael McKenry caught only 11 percent last season.
The Pirates have also benefitted by the emergence of Pedro Alvarez as a defensive force at third base. From 2010-12, Alvarez ranked 28th out of 31 major league third basemen who have played 1,500 innings in UZR (-15.0). This season, Alvarez ranks 12th.
While the Pirates enter the weekend with a major league-leading 3.16 ERA, their team batting average on balls in play is .270 -- well below the league average of .293.
In this case, it's the defense -- not luck -- that deserves the credit for that difference.
Looking ahead: Going into the break ...
The Pirates finish the pre-All-Star break portion of their season with a six-game homestand. They will play host to the Oakland Athletics for a three-game series beginning Monday. They previously played the Athletics in 2010, when they were swept in a three-game series in Oakland. The Athletics previously visited PNC Park in 2002. Have the Pirates become a story? Although Wednesday's game will still be shown locally on Root Sports, ESPN will televise it to the rest of the country.
The Pirates finish the first half with a three-game series against the New York Mets beginning Friday. They took three of four games against the Mets in May at Citi Field.