ATLANTA — Ronald Acuña Jr. wasted no time testing the New York Mets’ ability to control the running game, which has popped up as an early issue for the club.

With a decent lead at first base, the Atlanta Braves star and reigning National League Most Valuable Player took off for second base after a good jump on the first pitch. Mets pitcher Adrian Houser wasn’t slow to the plate, but it didn’t matter. Acuña likely would’ve swiped second base on a decent throw, but Omar Narvaez’s attempt gave the Mets no chance. The ball sailed into center field, and Acuña took third base, too. It was the first inning of the Mets’ 6-5 loss to the Braves on Tuesday. Acuña soon scored the game’s first run.

Acuña’s running — and the Mets’ inability to stop him — continued in the fourth inning. That’s when he stole second base and third base within two pitches. Neither play was particularly close — on the play at second base, Narvaez made a good throw but seemed to take some time releasing it, and it appeared Acuña took the Mets by surprise when he swiped third base. In one game, Acuña racked up three stolen bases.

Through 11 games, the Mets (4-7) have allowed 21 stolen bases, more than any other team.

Also, the Mets are the only team yet to catch a runner attempting a steal.

Different 🔥@ronaldacunajr24 | #BravesCountry pic.twitter.com/OcmH2GN3nP

— Atlanta Braves (@Braves) April 10, 2024

“We’ve been playing some teams with elite speed,” Mets manager Carlos Mendoza said. “And here we are playing one of the best base stealers in the game in Acuña. They’re going to be aggressive. It’s something that we are going to continue to work on, continue to talk about it. But not concerned.”

Mendoza made a fair point. The Milwaukee Brewers are a young team featuring dynamic position players like Jackson Chourio. The Cincinnati Reds boast a similar group led by Elly De La Cruz. Like Acuña, those players are going to successfully steal against teams more often than not. The thing is, the Mets also can’t afford to have players like the Detroit Tigers’ Colt Keith (he had a stolen base against the Mets last week and isn’t considered a burner in regards to speed) steal on them, too. That’s when an early-season issue against good running teams becomes a concerning problem.

Opposing scouts have attributed the stolen bases to a variety of reasons. It’s not just on Narvaez, the backup who has allowed 11 stolen bases. Both Narvaez and Francisco Alvarez have looked slow at times with exchanges — the time it takes for them to release a throw after receiving a pitch. Other times, pitchers have done a poor job holding runners. And, like Mendoza suggested, there are also times where a good throw, good exchange and quick time to the plate from the pitcher still resulted in a stolen base. Whatever the reasons, it’s on the catchers, pitchers, pitching coach Jeremy Hefner and catching coach Glenn Sherlock to fix.

“Obviously, we got to get better,” Narvaez said, “but it’s not only for us; those teams are going to run (against) anybody.”

The Mets cannot afford to continuously have instances where they give up bases. In spring training, they prioritized controlling the run game and had good results. That has not translated during the regular season. Mendoza suggested incorporating more slide steps, showing different looks and holding the ball longer on the mound at times as ways to improve.

Narvaez offered another.

“Keep them off the bases,” he said. “That’s basically it.”

Martinez’s arrival hits a setback

J.D. Martinez needs more time.

After reporting body soreness a few days ago, Martinez received a cortisone injection in his lower back Tuesday to treat tightness in the area.

Martinez will not see action in the minor leagues for three to five days, which pushes back his timeline of joining the Mets.

After the recovery period, Martinez will remain in Port St. Lucie, Florida, and continue to ramp up in Low-A, Mendoza said. Martinez arrived to the Mets on a one-year contract worth $12 million just before spring training concluded. He agreed to let the Mets option him to the minor leagues so he could build up for the season. After appearing in two games for Low-A St. Lucie last weekend, he was given two days off with what was termed “overall body soreness.”

Martinez, 36, has dealt with back issues in recent years, including last year with the Los Angeles Dodgers. Mendoza said Martinez told him he received a cortisone shot last April for lower-back discomfort, and it worked well.

“The way that he described it was last year he was swinging a bat within six days,” Mendoza said. “So we’ll see how the next 48 to 72 hours he responds to the treatment, and then we’ll go from there. But as far as at-bats and things like that, he feels really good timing-wise, mechanics. So I’m not too concerned about this.”

Pitching notes

• While Luis Severino experienced better results in his second start compared to his debut, the Mets would like to see more vertical movement or “ride” on his fastball. In spring training, Severino consistently showed he was capable of that. To some evaluators, it’s important because it helps distinguish the pitch from his slider.

• Reliever Dedniel Núñez pitched two solid innings in his major-league debut Tuesday but packed a bag after the game inside the Mets’ clubhouse. Needing another fresh reliever Wednesday, New York is expected to send him back down.

• In the offseason, multiple club officials saw Reed Garrett as an intriguing bubble reliever for the roster that they wanted to hold onto. So far, he has rewarded their belief in him. Considering their bullpen has been taxed, the Mets could’ve optioned Garrett — he is the rare reliever with the Mets carrying a minor-league option — but they’ve chosen not to. He has pitched too well. In 5 1/3 innings, he has yet to allow a run and has recorded nine strikeouts.

(Photo of Ronald Acuña Jr. stealing second base: Todd Kirkland / Getty Images)