Locke's numbers have impressed Pittsburgh manager Clint Hurdle, but the skipper is more enthused by Locke's approach.
"His preparation, his focus, his command, there's more in front of him," Hurdle said. "He's not satisfied."
Perhaps chief among Locke's strengths is his consistency.
Although Locke was not at his best in Friday night's 2-0 loss to the Marlins, he gave up three earned runs or fewer for a 17th consecutive outing and notched his fourth straight quality start on the road.
While talented, few expected Locke to enjoy a breakout year in his first full MLB season. Hurdle was blunt when asked what he thought of remaining doubts lingering around Locke.
"The critics probably didn't have him on the team," Hurdle said. "And they sure didn't have him winning nine games. So why not throw it out there that the second half won't be as good? Sooner or later, they might be right about something.
"I don't think many people had him making the All-Star team. I didn't. He's done things that I think only, at the end of the day, he believed he could get to. He's kept [critics] quiet, and he keeps doing it."
Critics may become louder if Locke endures more nights like his one on Friday. He gave up a season-high-tying eight hits in 6 2/3 innings, and his six walks were one shy of his season-worst total.
He threw first-pitch balls to 13 batters on Friday night, including four straight to begin the sixth. Opposing batters reach base against Locke at a .396 clip when beginning with a 1-0 count, compared to a .195 OBP when he throws a first-pitch strike.
"He pitches on edges at times," Hurdle said. "It's not uncommon for him to get some three-ball counts, and they got away from him [Friday]."
But when Locke puts guys on base, he usually strands them. Miami was just 1-for-6 with runners in scoring position and left 10 men on base against Locke.
Opponents are batting only .122 (9-for-74) against Locke with runners in scoring position. With men on base, Locke holds batters to a .193 (31-for-161) clip.
Walks have been an issue for Locke, whose 4.22 per nine innings are the most among Pirates pitchers with seven starts or more. Although Locke has minimized damage with men on base, he acknowledges his walk rate could spell trouble down the road.
Especially on nights when he is allowing more than his rotation-best rate of only 6.29 hits per nine innings.
"It's obviously something you'd like to command better," Locke said. "At the same time, I haven't really been giving up a whole lot of hits either. Whether they're walks or they're hits, they never really show up on the same night, but [Friday] they did."
Hurdle attributes Locke's walk rate to the fact that opposing batters have learned more about the left-hander, resulting in increased plate discipline.
However, considering the stellar season Locke is enjoying, Hurdle believes experience is the answer to Locke establishing better control moving forward.
"He set the bar extremely high early, and I still don't see him as a finished product," Hurdle said. "He's going to grow and learn and get better. And I expect those walk numbers will go down as he continues to pitch."