With the game tied in the ninth inning, Cardinals Manager Mike Matheny calls on right-hander Michael Wacha (pictured), whose last appearance in a major league game came 20 days earlier. (Kyle Terada/Usa Today Sports)

At the top of a staircase under the stands at AT&T Park, Mike Matheny stood, the glare of television lights shining on his full St. Louis Cardinals uniform, a blank stare on his face. At the bottom of those stairs, near the dugout, clubhouse attendants stacked the Cardinals’ red equipment bags, ready for the bus ride to the airport, ready for the flight home, ready for winter.

What is a man thinking in that moment, when his season has ended with a deadening thud, a thud he helped create?

“I put [Michael Wacha] in a tough spot,” Matheny said, and whatever he thought, however much he will stew, he spoke the truth.

The Cardinals’ season is over now, ending in Game 5 of the National League Championship Series, won by the how-the-heck-do-they-keep-doing-this San Francisco Giants, 6-3, on a ninth-inning homer from Travis Ishikawa, the latest hero for a franchise that has won three pennants in five years.

“What a great story,” Giants Manager Bruce Bochy said, and there will be plenty of time to tell it because the World Series doesn’t begin until Tuesday in Kansas City, of all places. For now, we have the continuation of a postseason that has been defined by the managerial decision. Each game, sliced open to reveal the ingredients from which it was made, has been spectacular. But how many more pivotal points can there be for managers?

Ned Yost is either in the World Series despite himself or because he learned from his mistakes. Long gone are the decisions made by Matt Williams to take Jordan Zimmermann out of a shutout, by Bob Melvin to stick with a tiring Jon Lester as an eighth-inning lead slipped away, by Don Mattingly to call on little-used reliever Scott Elbert in a key spot.

So here was Matheny, in the visitors’ dugout, bottom of the ninth inning, tied 3-3 because pinch hitter Michael Morse had tattooed an offering from all-star setup man Pat Neshek in the eighth, keeping the Giants alive. But there is so much else Matheny might be thinking of behind that vacant stare.

Not appearing in the final game for St. Louis: Trevor Rosenthal, the closer who throws 100 mph and saved 45 games this season. With two Giants already on base, three consecutive left-handed hitters were ready to come up. Yet veteran lefty Randy Choate stood, warm but idle, in the St. Louis bullpen.

Wacha remained on the mound.

“He was the hero of this last year,” Neshek said.

Last year? That was before injuries limited him to 19 starts in 2014.

“I can tell you right now there’s nobody I would rather have on the mound right there than Michael Wacha,” stalwart right-hander Adam Wainwright said. “He’s one of the greatest competitors I’ve ever played with.”

Yet he hadn’t competed in 20 days. So here was the spot: tie game, switch hitter Pablo Sandoval leading off, right-handed Hunter Pence up next, the three lefties — Brandon Belt, Ishikawa and Brandon Crawford — to follow.

“That was actually kind of what we were planning on using him for, [if] we get to those extra-inning spots,” Matheny said. “It’s gonna be challenging to get him further than one inning. We like Michael’s stuff right there.”

Wacha is 23. His stuff is electric. A year ago, he came within an out of no-hitting the Washington Nationals in his final start of the regular season, then won his first four starts of the postseason, posting a 1.00 ERA, striking out 28 batters in 27 innings.

“He’s amazingly talented,” said Wainwright, the Cardinals’ veteran ace. “I can’t wait to play with him for the next few years.”

But Wainwright is already talking about the future because the present slipped away — and quickly — Thursday night. The decisive inning went like this: Wacha pumped in two strikes to Sandoval, who shrugs off that kind of stuff every single October day. He took a ball, then laced a single to right. Joaquin Arias pinch-ran for him, the winning run.

Wacha then got Pence to fly out to right, a ball that was fairly hard hit. And here came Belt, the left-hander. Marco Gonzales, the rookie lefty who St. Louis had used to great effect, was spent from throwing the previous two games, unavailable. Choate, though, had been warming in the bullpen.

“Liked Wacha,” Matheny said. Plus, he figured Bochy would counter with a right-handed hitter had Choate come in. But with Morse already spent, the right-handers he had available were Juan Perez, a light hitter, and rookie infielder Matt Duffy, on the roster for his speed.

Wacha threw Belt four straight balls. The winning run moved to scoring position.

“Any guy we put in there, it’s a tough situation,” Matheny said. “Michael, his stuff looked good. I don’t know if anybody could expect him to be as sharp as he normally would. He needs consistent time. But that’s on me.”

Matheny is a straight-jawed former catcher in his third year of managing a big league team, his only managing or coaching experience at any level. He is not alone in this spot, and he has led his team to the playoffs in each of his seasons in St. Louis. In the aftermath, he moved into the manager’s office just off the silent visiting clubhouse. Black-and-white photos of Hank Aaron and Mickey Mantle hung on the wall. He stared ahead, resolute, even though Choate — who held lefties to a .093 average this year — was ready, even though Wacha fell behind Ishikawa 2-0.

“I knew that he didn’t want to get behind 3-0,” Ishikawa said. “Chance of walking the bases loaded.”

So Wacha, dormant since Sept. 26, unleashed one final fastball, the last pitch of the St. Louis Cardinals’ season. It ended up in the right field seats.

“Put him in a tough place, without getting much work here lately,” Matheny said. “That’s on me.”

Players always say: Good managers put their players in position to succeed. In the ninth inning Thursday, Mike Matheny put Michael Wacha in a position to fail.

Pitchers and catchers report in February.