When the Pittsburgh Pirates added All-Stars Brandon Lowe and Ryan O’Hearn this offseason, it was with the intention of bringing some pop to a lineup that too often fell flat last season.

Lowe and O’Hearn have been as advertised through the first four games, as both are batting better than .400 and have combined for four home runs and seven RBIs.

That the rest of the starting lineup is hitting .139 (10 for 72) has been a major problem for the Pirates, who are 6 for 45 with runners in scoring position so far this season.

“Always early in the season, especially when you’re struggling, everything gets magnified,” Pirates manager Don Kelly said Monday night on the SportsNet Pittsburgh postgame show. “Lowe and O’Hearn have been really strong. We’re going to need everybody to chip in. They certainly will. Especially early on here, we’re starting to feel the pressure. We need everyone to stay within themselves and keep battling and we’ll come up with some big hits.”

The Pirates failed to do that in a 2-0 loss to the Cincinnati Reds on Monday, when they left eight runners on base. They had runners in scoring position in the fifth, seventh and ninth innings but failed to come through.

In the fifth, Nick Gonzales stole second base with one out but Chase Burns struck out Henry Davis and Oneil Cruz to prevent any damage. In the seventh, Reds reliever Graham Ashcraft struck out Davis with runners on first and second.

The worst part came in the ninth, when Connor Phillips walked Marcell Ozuna on four pitches and O’Hearn on a full count. Despite Phillips struggling with his command, Jared Triolo chased a first-pitch sweeper outside the strike zone and ended up going down looking at a called third strike on a sweeper at the bottom of the zone. Triolo motioned like he was going to tap his batting helmet to challenge the call through the automated ball-strike system but decided against it.

“There’s certainly a learning curve,” Kelly said of ABS challenges. “Talking to the guys, we want to be more aggressive on pitches we’re more convicted in. I didn’t see the replay, so I don’t know if it was a strike or not, but we want to be more aggressive on the right pitches, if we can.”

Spencer Horwitz followed with a fly out to left before Gonzales hit a pop fly that second baseman Matt McLain caught to end the game. Kelly said the Pirates were going for the win, but that the key is for their hitters to stay within themselves in their approach at the plate.

“That’s the thing: When you start to press, you get outside of the approach,” Kelly said. “That’s what it looked like to me after those two walks.”

The Pirates were 6 for 39 with runners in scoring position in their three-game series against the New York Mets, going 2 for 18 Saturday in a 4-2 walk-off loss in 11 innings and 3 for 14 Sunday in a 4-2 win in 10 innings. Monday marked the second time in four games that the Pirates didn’t score a run through nine innings.

“Over the course of the season, that’s not going to be good enough,” Kelly said. “Our guys are working hard at it.”

Through the first four games, Gonzales (5 for 18, .278) is the only other starter to join Lowe and O’Hearn in batting above the Mendoza Line. The Pirates desperately need better production from Cruz (2 for 14, .143) and Bryan Reynolds (3 for 18, .167) and especially Horwitz (1 for 11, .091) and Ozuna (1 for 12, .083).

Yet Kelly remains optimistic that the Pirates will turn it around.

“Easier said than done. I’ve been there myself. It’s difficult when that starts to happen,” Kelly said. “With Lowe and O’Hearn leading the way, other guys will jump on board and we’ll start to come up with big hits.”