How will the Phillies’ Zack Wheeler react to the playoff stage? His former coach knows.

ST. LOUIS — In bracing for his first career postseason start, Zack Wheeler recounted his most nerve-racking moments on a baseball field. He thought about the 2012 Futures Game in Kansas City and the 2021 All-Star Game in Denver. He remembered the pterodactyls churning in his stomach, the pounding in his chest.

“I’ll just kind of look back at those and how I handled that and go out there and stay the same,” Wheeler said Thursday before the Phillies worked out at Busch Stadium on the eve of their first playoff game in exactly 11 years. “Those are some different moments for me that I kind of had to settle myself down for. I’m sure it’ll be the same.”

» READ MORE: Two key Phillies state the obvious: ‘Of course’ Rob Thomson should return as manager

Maybe. But October tends to have a strange effect on even the best pitchers. For every Roy Halladay, who tossed a no-hitter in his first playoff start in 2010, there’s a Clayton Kershaw, who has a 2.48 ERA in his career and a 4.19 mark in the postseason.

It’s fair to wonder, then, how Wheeler will react to the added pressure, the increased scrutiny that comes with pitching in the playoffs.

Tony Boyd says he knows.

And he still has the score book to prove it.

Boyd was Wheeler’s coach at East Paulding High School in Dallas, Ga., not far from Atlanta. In 2009, the Raiders went to the state tournament and advanced to the semifinals. In three starts over three rounds, Wheeler struck out 37 batters, according to Boyd’s record-keeping, including a 13-strikeout no-hitter in a 9-0 victory over Mill Creek in the second round on May 14, 2009.

It was after that game, as East Paulding congratulated Wheeler, that the opposing coach shook Boyd’s hand and said, “I’ve been around a lot of ‘em, Coach, and he’s the very best I’ve ever seen. It was a man among boys today, and believe me, we weren’t the men.”

“He was pretty darned special,” Boyd said by phone Thursday.

Boyd laughed at the memory. And he knows some people may chuckle at the idea that a high school tournament from 13 years ago could portend success in Game 1 of the best-of-three National League wild-card series on the road against a St. Louis Cardinals team that won 93 games and a division title in the final seasons for Albert Pujols and Yadier Molina.

» READ MORE: Former Cardinal Edmundo Sosa hopes to be added to the Phillies’ playoff roster

The stakes are far higher now — for Wheeler, the Phillies, and a fan base that is starving for new postseason memories.

But there was plenty riding on those games for 18-year-old Wheeler. The draft was a few weeks away, and the bleachers at East Paulding’s field were packed with 15-20 scouts at every game, as Boyd recalled. Heck, a crowd would gather as Wheeler warmed up in the bullpen.

“It didn’t matter how many of them were watching,” Boyd said. “He handled it as well as anybody I’ve seen. One of the best features he had, still has, is his demeanor. He just has a way of keeping it steady. It’s not like it’s going to overwhelm him.

“Now, this is going to be on the biggest stage and there’s a lot more pressure to it than a high school game. But if he can maintain that demeanor and just pitch with confidence and pitch like he’s capable, I think he’s going to be just fine.”

Wheeler describes himself as “laid back.” Hitters who face the fury of his 96-mph fastball, unleashed from a silky-smooth delivery, surely differ.

Despite not making a start in spring training and missing a month late in the season with elbow inflammation, Wheeler made 26 starts and posted a 2.82 ERA and 163 strikeouts in 153 innings. He faced the Cardinals in back-to-back starts in July and tossed seven scoreless innings each time.

There’s no overstating how much it means for the Phillies to hand the ball to Wheeler in Game 1 — or how much they need to win it.

» READ MORE: Phillies playoffs: How I was wrong about this team — and you probably were, too

“He’s one of the best pitchers in the game, so when you hand him the ball, you really feel good about what the outcome’s going to be,” interim manager Rob Thomson said. “It’s not always there, but you feel good about it going in.”

Six weeks ago, the Phillies couldn’t be sure that Wheeler would be ready. He went on the injured list Aug. 25 after feeling a twinge in his right forearm, near the elbow. He insisted he could keep pitching, but team officials convinced him that taking two weeks off would be beneficial. Two weeks turned into a month when Wheeler felt lingering soreness and an MRI revealed inflammation.

» READ MORE: Zack Wheeler’s ‘good rest’ appears to be a shrewd gamble by the Phillies

Earlier in his career, Wheeler was unable to pitch in the postseason for the New York Mets because he was recovering from Tommy John elbow surgery in 2015 and dealing with a strained flexor tendon in 2016. But this wasn’t that. Wheeler reiterated Thursday that he was never concerned about being ready for the postseason — or even the Phillies’ late-September push to get in.

Indeed, Wheeler returned on Sept. 21 and threw harder than before in four scoreless innings against the Blue Jays. His pitch count rose from 58 to 62 on Sept. 27 in Chicago and 77 last Sunday in Washington. The Phillies hoped to get him closer to 90 pitches, but wet conditions, a slippery mound, and an eight-run lead conspired to make them take him out after five innings. He hasn’t pitched in the seventh inning since Aug. 3.

Is Wheeler ready for a typical workload in Game 1?

“I think so,” he said. “I’ve pitched in the sixth. [It’s just] one more inning. We’ll be all right.”

Said Thomson: “I think he’s fine and we’re in playoff mode now, so he’s full-go. Would’ve probably liked a few more pitches out of him in his last start, but we didn’t get it. But he’s good to go.”

Boyd, who keeps in contact with Wheeler mostly via text messages, has no doubt.

“I’ve told several people, watching him pitch some this year — and I know it’s no comparison because we’re talking about Major League Baseball — just watching his comfort level and his confidence, that was his demeanor and the way he pitched his senior year. It was like, ‘Hey, I’m the best guy out here.’ And you could just see that in the way that he performed.”

Then, and maybe now.

» READ MORE: Phillies in the playoffs: What you need to know about the Cardinals, and what’s changed since 2011