OAKLAND -- Right-hander Peter Lambert took the walk of dejection after delivering the bases-loaded four-pitch walk Thursday afternoon to seal a defeat that was barely fathomable but is fitting for the 2024 Rockies’ bullpen.

Lambert’s walk to pinch-hitter Tyler Soderstrom completed a five-run collapse in the bottom of the 11th inning of a 10-9 loss to the Athletics at the Coliseum. The walk was fourth of the day by the Rockies’ relief core -- and the maddening MLB-worst 99th issued by their bullpen in 178 1/3 innings this season.

The Rockies (16-33) will address the problem individually, collectively and from an instructional standpoint. But, like Lambert’s walk (after the Rockies intentionally passed Kyle McCann with two outs to create a force at any base), the issue endures. Like on Thursday, the defeats they cause can be excruciating.

“This was no different,” Lambert said. “Obviously, the situation was a little bit bigger. Bases loaded, you can’t walk a guy there, because if you do, the game’s over. I just didn’t execute a few pitches.”

The collapse occurred after the Rockies, who led 4-0 going into the bottom of the seventh behind starter Ryan Feltner’s six strong innings, built a 9-5 advantage in the top of the 11th -- largely against Mason Miller, the Athletics’ remarkable rookie closer.

But it didn’t stop with the walks. Crushable pitches in the strike zone are the evil offspring of walks. Every reliever Thursday gave up a run (although the one against Justin Lawrence was unearned, scored by the automatic runner in the 10th). Usually solid righty Victor Vodnik yielded three hits and one run in the seventh, Tyler Kinley coughed up a two-run homer to J.D. Davis in the eighth, and Jalen Beeks surrendered Daz Cameron’s leadoff homer in the ninth.

Matt Koch, a day after his save in Wednesday’s 12-inning victory, coughed up four runs (three earned) and three hits without managing an out. Shortstop Ezequiel Tovar nearly rescued Lambert with a sliding backhand play on Zack Gelof's sharp grounder with two out, but the long throw was too late to prevent a single.

“I was going in to attack the zone and try to make some quality pitches, but I made some mistakes and they put good swings on them,” said Koch, who lost the lead on Max Schuemann’s RBI double, Abraham Toro’s RBI single and JJ Bleday’s two-run homer.

“The bullpen guys struggled -- it was a really tough one for those guys,” Rockies manager Bud Black said. “As good a win as it was yesterday [on Ryan McMahon’s 12th-inning homer] in extras, this was a tough one today.

“But we’ll bounce back.”

Thursday’s loss, though, fit a disturbing pattern for Colorado.

Cal Quantrill held Oakland to two runs and three hits in six innings Tuesday, but the Rockies lost, 5-4. Austin Gomber threw eight innings of one-run ball Wednesday. Feltner shut down the Athletics on Thursday by mainly using his power fastball.

A shaky bullpen is not a surprise.

The Rockies planned on closer Daniel Bard regaining his 2021-22 form, but he underwent Tommy John right elbow surgery without throwing in a game. Lawrence -- who escaped the 10th by forcing a Cameron double-play grounder -- and Kinley have not been consistent enough to handle closing.

“It can be a little frustrating, but there have been good stretches -- it’s just getting back in a groove and being able to do it for a long time,” Lawrence said.

How can the Rockies be led to quality areas of the strike zone?

“It’s conversations daily, just coaching,” Black said. “It’s a combination of mechanical, mental. There’s early work. It’s trying to get the mindset in the right spot. Guys are trying. There’s a little bit of a walk in their history. My challenge, even last year, is we’ve got to get incrementally better.”

There are no magic words. Even logical ones can do harm.

“When you harp on it, it can be in the forefront of guys’ minds,” Kinley said. “The biggest thing is guys -- me included -- all just need to trust our stuff in the zone, have our sights in the zone and be aggressive there.”

Beeks, who was the team’s best ninth-inning pitcher until this week, was claimed from the Rays in the offseason. He said there is a unique adjustment between home and road, but said, “That’s part of the battle, and it makes you a better pitcher.”

But until their relief pitching is better, there’s no safe lead for the Rockies -- even four runs in the 11th inning.