CINCINNATI — Even as the Dodgers clinched a postseason berth with their 4-1 win over the Reds on Monday, bullpen uncertainty loomed.

When they get to the playoffs, who’s going to take the ball in high-leverage situations?

Their options are dwindling. Edgardo Henriquez landed on the 15-day injured list Monday with low back discomfort, ruling him out for the rest of the regular season. Edwin Díaz was so shaky in his rehab assignment Sunday that a spot on the postseason roster isn’t guaranteed.

“We have to go with our best pitchers, as far as performance, talent, all that stuff,” manager Dave Roberts said before the Dodgers opened a four-game series against the Reds. “So my bet is that he will be [on the roster]. But there’s got to be some kind of evidence or something for us to sort of bet on. And so my bet is, yes, but we’ve still got to see something.”

Díaz (neck) had the worst outing of his triple-A rehab assignment, surrendering five runs and issuing two walks in two-thirds of an inning. The dud put his return timeline in doubt. His next rehab appearance is scheduled for Wednesday.

“I think the world of him, the baseball card looks great,” Roberts said. “But where we’re at, there’s got to be something for us to be able to hang our hat on. And he knows that. He knows that. He wants to pitch well. So for me, Wednesday, we’ll be watching closely.”

So, who’s still in play?

Tanner Scott remains Roberts’ go-to in save situations. And Alex Vesia, Evan Phillips, Brock Stewart, Jack Dreyer and Blake Treinen all have experience in late innings.

On Monday, starter Tarik Skubal gave the group a much-needed break with seven shutout innings. He limited the Reds to three hits and a walk, cruising through their lineup almost three times in 90 pitches.

The Dodgers pulled ahead by four runs, on home runs from Kyle Tucker and Teoscar Hernández, who have both broken out of slumps, and an RBI single from Kiké Hernández.

With the game still relatively tight, Vesia entered in the bottom of the eighth to face the left-handed heavy bottom of the order. He retired the side.

Phillips and Treinen both were warming in the ninth when the Dodgers got a runner to second base with one out. When they failed to score him, Phillips jogged in to face the top of the order. He surrendered a high-flying solo homer to Elly De La Cruz on a fastball above the zone but avoided further damage.

Before the game, the Dodgers added two fresh arms to the bullpen. They recalled right-handers Bobby Miller and Paul Gervase, as they put Henriquez on the IL and optioned right-hander Emmet Sheehan.

Henriquez will undergo imaging on the area, which Roberts said stretched to his side near his oblique.

“The hope is we’ll get him back in the postseason,” Roberts said.

Roberts said he didn’t know what the move meant for Sheehan, who in his past two starts limited opponents to one run and recorded 15 strikeouts in a combined 11 ⅔ innings.

“Some of it’s probably contingent on Roki [Sasaki], and we’ve got another start coming up down the road here, as far as a bullpen kind of situation,” Roberts said. “So I don’t know, but Emmet’s done everything he can do in his power to force our hand, which I love. The last two have been really good.”

Sasaki (right middle finger blister) could start Thursday. His bullpen session Monday marked the first time he had tested covering the sensitive area on his finger with Dermabond, Roberts said.

“We just can’t put him in a position to go backward,” Roberts said.

The Dodgers also have more bullpen reinforcements coming.

Pitcher Kris Bubic delivers during a game between the Kansas City Royals and Chicago White Sox.

Pitcher Kris Bubic delivers during a game between the Kansas City Royals and Chicago White Sox in May.

(Jayden Mack / Getty Images)

Another bullpen addition is left-hander Kris Bubic, who met the team in Cincinnati and is in place to make his Dodgers debut later this week. Bubic made his last rehab appearance for triple-A Oklahoma City on Sunday, so Roberts said the Dodgers likely won’t activate him off the 60-day injured list until Wednesday at the earliest.

The Dodgers acquired Bubic from the Kansas City Royals at the trade deadline this year. He’d been on the IL since May, first with a low-grade flexor strain in his left forearm, and then a shoulder impingement setback.

In six triple-A rehab appearances over 5⅔ innings, Bubic didn’t yield a run and he limited opponents to two hits and two walks.

Roberts was noncommittal about Bubic being a high-leverage option.

“Seems like all of our games are leverage these days,” he said.