PHOENIX -- Craig Kimbrel dropped to a knee as soon as the ball left the bat.

He knew.

Alek Thomas barreled a 3-2 fastball in the eighth inning Friday night in Game 4 of the National League Championship Series at Chase Field. He sent the pitch over the right-center-field wall for a game-tying two-run home run. Four batters later, the D-backs scored the go-ahead run, giving them a 6-5 victory to even the best-of-seven series and tilt momentum to a team that appeared overwhelmed and overmatched after Games 1 and 2 in Philadelphia. The Phillies now need Zack Wheeler to outduel Arizona ace Zac Gallen in Game 5 on Saturday or they will face elimination in Philadelphia on Monday.

“We wouldn’t want anybody else on the mound,” Phillies catcher J.T. Realmuto said. “Wheels is our guy.”

Wheeler said before Game 4 that he wants to pitch a complete game every time he starts, but he understands today’s emphasis on health and the effectiveness of bullpens make those opportunities rare. But a Game 5 complete game from Wheeler would be a godsend now that there are serious concerns about the Phillies’ bullpen, which imploded the past two games.

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It starts with Kimbrel. He had not allowed a run over his first four postseason appearances, but he had put runners on base and given up hard outs. Kimbrel began to unravel when he allowed a single to Ketel Marte for a walk-off loss in the ninth inning in Game 3 on Thursday. Then he struggled again in Game 4.

Thomas’ blast was the first game-tying or go-ahead homer Kimbrel had allowed in his postseason career. It was his first blown save (he had been 10-for-10), although he posted a 6.14 ERA in six saves with the Red Sox in 2018 before he lost his job at the end of the World Series.

Kimbrel is the first Phillies reliever to lose consecutive games in a single postseason. The only other relievers to lose multiple games for Philadelphia in a single postseason are Mitch Williams in 1993 and Tug McGraw in '80.

The Phillies are hoping for a 1980 finish, not a '93 one.

“I've been in the big leagues for a long time,” Kimbrel said. “I've lost a lot of ballgames and I've won a lot of ballgames. The only way you come back and be successful is believe that you can. And I believe the next time I touch the ball, it's going to be great.”

But Phillies manager Rob Thomson’s trust in Kimbrel might be shaken. Does Kimbrel expect his skipper to give him another opportunity in a big spot, considering his struggles to find the strike zone and the magnitude of these games?

“That’s really up to him,” Kimbrel said. “I’ll be ready to take the ball whenever he gives it to me.”

“We have to talk about it, but do you put him in at a little lower-leverage spot?” Thomson said. “I don't know. I'll talk with [pitching coach] Caleb [Cotham] and talk through it and see where we're at.”

But it isn’t just Kimbrel. Left-hander Gregory Soto replaced Seranthony Domínguez with one out in the seventh. It was Soto’s first appearance in eight days. He allowed a single and a walk to put runners on first and second, then he got Corbin Carroll to hit into a fielder’s choice to put runners at the corners with two outs.

Rookie right-hander Orion Kerkering entered. He allowed one run and three hits to the only three batters he faced in Game 3. Kerkering, who was pitching on consecutive days for the first time in his professional baseball career, walked Gabriel Moreno to load the bases. He then walked Christian Walker to force in a run and cut the Phillies’ lead to 5-3.

After Kerkering hung a couple of sliders in Game 3, he said he overcorrected and yanked his sliders in Game 4.

“I think just location, honestly,” Kerkering said. “I'm just overthinking that aspect of it.”

Where does this leave his confidence?

“Where it needs to be,” Kerkering said. “Just be ready for every moment every single time, no matter the situation.”

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After Kimbrel allowed the homer to Thomas in the eighth, he got the second out by fanning Geraldo Perdomo, then he allowed a single to Marte. Carroll stepped into the batter’s box. Left-hander José Alvarado was ready, but Thomson chose not to use him. Kimbrel promptly hit Carroll with a pitch to move the go-ahead run to second base.

Only then did Alvarado enter. Five pitches into his outing, he allowed the game-winning hit to Moreno.

It was puzzling. It was demoralizing. It left everybody wondering how Thomson will manage his bullpen in Game 5. Kimbrel, Kerkering, Alvarado and Jeff Hoffman have pitched the past two days. Thomson does not like using relievers three days in a row.

So who’s available that he can trust?

The Phillies are carrying right-handers Taijuan Walker and Michael Lorenzen on the 26-man roster, but they are being held for length or emergency situations (i.e. extra-inning games). It has left Thomson shorthanded. Expect to see left-hander Ranger Suárez in the bullpen in Game 5. He pitched well in relief last postseason.

This series should not have come down to the Phillies needing a season-saving performance from Wheeler with a potential bullpen appearance from Suárez to win Game 5, but now it’s their reality.

“I think I just look at it as now it’s a best-of-three series and we have home-field advantage, and we have Wheeler and [Aaron] Nola lined up,” Nick Castellanos said.