ST. LOUIS -- The fastball to J.D. Martinez may have been the pitch Luke Weaver most wanted back, but it was a changeup that wasn't chased moments earlier that offered Weaver the most lasting lesson in Thursday night's 4-0 Cardinals loss to the D-backs.
In the middle of a four-run inning that would stain his first Major League start of 2017, Weaver was reminded that what has helped him to four seasons of tremendous Minor League success doesn't always translate seamlessly to this level.
Urged by manager Mike Matheny to be more aggressive around the strike zone than he was in a string of starts last season, Weaver came out challenging Arizona's offense early. He struck out four the first time through the order and eased through three scoreless innings on 43 pitches.
But the night grew more complicated in the fourth, which opened with a double by A.J. Pollock. Weaver then walked Jake Lamb on a full-count fastball and threw a 3-2 changeup to Paul Goldschmidt that wasn't enticing enough for the cleanup hitter. Goldschmidt laid off the borderline offering to load the bases.
"I thought that pitch to Goldschmidt was a pretty good thrown ball and that's a big league take," Weaver said. "That just puts more pressure on me. In a moment like that, I just have to execute a little better."
Five pitches later, Martinez snuck a grand slam around the right-field foul pole for a 4-0 D-backs lead.
"He throws a 3-2 breaking ball to Goldschmidt there that, I would say, through his career, I'll bet a high percentage of people swing through that. And there's just a different level here," Matheny said. "That ran him into a ball four and then he has to challenge a guy. And yeah, at that point, he probably left that ball over too much of the plate and up in the zone to a strong hitter."

Figuring out how to utilize his repertoire more effectively remains the next hurdle to clear for Weaver, who is still seeking to prove that his 1.81 ERA over 51 Minor League starts has him ready for the Majors.
Last season, Weaver watched big league starts unravel when he tried to be too fine around the strike zone. Thursday's revelation was more nuanced, but nonetheless critical as Weaver tries to figure out how to maximize his repertoire against more patient hitters.
"When that big inning came, nothing was lacking confidence-wise," Weaver said. "[It was] good hitters make good decisions up there. If that situation comes around again, I'm going to win that one because I know what happened when I didn't execute. I want to make sure it doesn't happen again."
When Weaver will get that next chance is not clear. Adam Wainwright (mid-back tightness) hopes to reclaim his rotation spot next week, which would preclude Weaver from needing to pitch in his place again. There remains, however, an uncertainty about the status of Lance Lynn, who could be dealt before Monday's non-waiver Trade Deadline.

If Lynn does go, Weaver would be the leading candidate to assume that opening in the rotation, as Thursday's performance did nothing to shake the Cardinals' confidence in him.
"I think it's going to take him a little bit of those hard lessons," Matheny said. "The answer is to attack in a good part of the zone. You might not get those chases that you get somewhere else. But overall, I thought he did a great job. His stuff looked sharp. Just one inning got him."