PHILADELPHIA -- Trailing two games to one in the National League Championship Series, the Padres will turn to right-hander Mike Clevinger for Game 4 on Saturday night in Philadelphia. But for how long, exactly?

“I’m going to go until Bob comes and tells me I can’t go anymore,” Clevinger said.

And therein lies the most critical of questions for Padres manager Bob Melvin. Clevinger has struggled lately, having posted a 6.52 ERA over his final six starts of the regular season. Then he allowed five runs (four earned) over 2 2/3 innings in Game 1 of the NLDS at Dodger Stadium. He’s also been dealing with an assortment of nagging injuries, including a balky right knee.

Melvin has a mostly rested bullpen, and it’s not an overstatement to say the Padres’ season might hinge on Game 4. So when does Melvin emerge and tell Clevinger he can’t go anymore?

“We'll see how it goes,” Melvin said. “Take it batter to batter.”

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Melvin officially made the announcement that Clevinger would start Game 4 following San Diego’s 4-2 loss in Game 3 on Friday night. The Padres are hoping they get the version of Clevinger who pitched six innings of one-run ball in his regular-season finale against the White Sox.

But they need to be prepared for the alternative. Should Clevinger struggle, San Diego has a host of multi-inning options behind him. If he were to exit early, Melvin could choose to piggyback left-hander Sean Manaea on top of the righty Clevinger, perhaps tilting some of the matchups in his favor.

But Manaea hasn’t pitched all postseason. He finished the regular season strong but posted a 4.96 ERA over 28 starts and two relief appearances. The Padres would presumably prefer to see Clevinger work a bit deeper into the game.

If he does, they could turn the ball to some of their high-leverage multi-inning weapons -- namely right-hander Nick Martinez. Setup man Robert Suarez has also proven capable of pitching multiple frames.

The Padres had an off-day after Game 2, and neither Martinez nor Suarez pitched in Game 3. Fellow right-hander Luis García, meanwhile, hasn’t pitched since Game 1. If Clevinger were to cover four innings, the Padres seem to have the arms capable of bridging the gap to closer Josh Hader.

That would, of course, come at a steep cost. With the possibility of playing five games in five days, the Padres would prefer not to gamble everything on Game 4. 

Then again, the stakes are massive. In AL/NL postseason history, only 14 teams (out of 91) have won a series after falling into a 3-1 hole.

“We’ve just got to come in and bring it tomorrow,” said catcher Austin Nola. “Put everything into winning one game. That’s all it is: Win one game.”

Ideally, Clevinger shoulders most of the burden. He says, physically, he’s feeling as good as he has at any point in the last month, perhaps benefitting from some additional rest. When he takes the mound on Saturday, it will be 11 days since his start against the Dodgers.

“This whole week’s been very encouraging,” said Clevinger, who threw a full 35-pitch bullpen session on Thursday. “Good confidence for tomorrow.”

As for pitching in October, Clevinger is no stranger to it, pitching in his fifth postseason spanning his time with Cleveland and San Diego.

“I’m definitely stoked to see this Philly crowd,” Clevinger said. “Going to try to silence them. But I just feel more confident with how my body’s feeling right now. I feel like I’m going to be able to go out there and be a lot more competitive.”