The Orioles’ improved bullpen has stood out as a bright spot so far in 2021, as it has helped keep them in more close games than in years past. Tight scores put added focus on some of the game’s finer points, a la baserunning and defense. It’s in that latter category that the O’s are still seeking better results.

The latest example came Wednesday, when a fundamental lapse was at the heart of their 3-0 loss to the Marlins at loanDepot park.

Looking to preserve a scoreless tie in the fifth inning, Bruce Zimmermann gave way to Maikel Franco charging in from third to field Trevor Rogers’ sacrifice bunt, which advanced Sandy León to second. But nobody backed up third, and the slow-footed León, seeing the base vacated, took it successfully. Zimmermann then came within one pitch of escaping the jam before allowing Jesús Aguilar’s go-ahead two-run double; four innings later, it stood as the game-winner.

“You can’t deny it changed the entire integrity of that inning,” said Zimmermann, who fell to 1-2 with a 4.57 ERA in four starts. “It’s been a while since we had to run those bunt plays and that’s completely on me having to be at third base. It definitely would’ve made it a lot easier having that guy on second base.”

Said León: “On that bunt, my first goal is to get to second base. I’m not fast. When I saw the bunt was to third and I saw [shortstop Freddy] Galvis on second base, I was like, ‘No one’s on third.’ So I took my chances.”

Recalling the play postgame, manager Brandon Hyde called it catcher Pedro Severino’s responsibility to back up third when the third baseman is drawn in as Franco was on the play. Zimmermann blamed himself, also noting how Aguilar’s hit would’ve scored León from second regardless. Either way, the O’s did little to help themselves recover, mustering just four hits against Rogers and two relievers. They were shut out for the second time in three games. Severino was not made available postgame to discuss the play.

“What lost us the game is that we didn’t score,” Hyde said. “We lost two games on the road trip and were shut out on both.”

But the snafu highlighted the difference between the O's and some other rebuilding teams they’ve matched up with in the early going, and it was reflective of the types of fundamental mistakes that have plagued their rebuild for several years. The kind that aren’t always measurable, yet have persisted while other parts of the roster showed progress.

Last week, the Orioles lost three of four to the Mariners by a combined four runs, due in large part to Seattle’s superior infield defense. A half-inning after Aguliar’s go-ahead hit, the Marlins benefited from Miguel Rojas’ diving play on Austin Hays to keep a leadoff man off base. Hays was also thrown out trying to stretch a single in the third, another little thing that, by the time the O's boarded their flight back to Baltimore, loomed large.

Miami leads MLB in infield Outs Above Average, while the Mariners entered play ranked third. The Orioles are 23rd in OAA and 25th in infield runs prevented, also ranking in MLB’s bottom third in the outfield versions of both metrics.

“It’s a tough one to swallow,” Zimmermann said. “I really wanted to get out of that, but I should’ve made a better pitch.”