CLEVELAND -- Through his first four starts of the season, lefty Reid Detmers looked like an ace and it appeared he was starting to reach his immense potential.

But Detmers has scuffled in three straight outings since then, getting hurt by three homers in his latest start in a 7-1 loss to the Guardians on Saturday night at Progressive Field. Detmers had a 1.19 ERA in 22 2/3 innings over his first four outings, but has registered an 8.15 ERA over his last three starts, with 16 runs allowed in 17 2/3 innings. He’s now 3-3 with a 4.24 ERA in 40 1/3 innings, and has to once again prove he can be a consistent starting pitcher going forward.

“It’s frustrating,” Detmers said. “It comes down to execution, I guess. That’s baseball. I have to live and learn. We’re going to get over this, we’re going to get past this. We just have to take it start by start and I’m looking forward to next week and a new challenge.”

This time, Detmers was plagued by homers from three players who have struggled offensively this season. He had otherwise done a solid job of limiting big flies, previously surrendering two this year, both of which came in the same start against the Orioles on April 22.

But in the second, he served up a two-run blast to Austin Hedges, who entered with a .111 batting average with no homers and three RBIs in 10 games this year. Detmers left a 1-0 fastball over the heart of the plate and Hedges didn’t miss it.

Two innings later, it was Ramón Laureano who jumped all over a first-pitch fastball from Detmers in the middle of the plate for a solo shot. Laureano has historically crushed the Angels, especially when he was with the A’s, but entered batting .151 with no homers and three RBIs in 22 games this year.

Detmers was efficient, which allowed him to reach the sixth inning on 67 pitches, but he seemed to run out of gas that frame while going through the middle of Cleveland’s lineup for a third time. Detmers, though, said he still felt strong that inning but was clearly disappointed he lost his command and walked three batters in the frame.

“It was a poor performance,” Detmers said. “I don’t have any other explanation. I just didn’t execute very well. I was feeling good and the two homers before that hurt but I didn’t think much of it. But the three walks in the sixth can’t happen. And they made me pay.”

It started when Detmers walked José Ramírez on five pitches to open the inning before walking David Fry on seven pitches to put two on with nobody out. He recovered by striking out Laureano and Andrés Giménez but walked Tyler Freeman on five pitches to load the bases.

He was left in to face the left-handed hitting Bo Naylor, who entered batting .179 with two homers and five RBIs in 24 games. He also had just one career homer off a lefty in 63 career plate appearances and had never hit a grand slam. When Detmers tried to sneak an 0-1 curveball by Naylor, it caught too much of the plate, and Naylor smacked it for a grand slam.

“It was probably right in his honey hole,” Detmers said. “I would’ve liked that one more away and off the plate.”

Angels manager Ron Washington said he was surprised to see Detmers give up the grand slam because he liked the matchup against Naylor and they told him to try to be careful with Freeman.

“He got to the point where he got to the sixth inning, where he had to go down and find out what he's made of, and he just left a pitch over the plate to a left hander and gave up a grand slam,” Washington said. “Never in my wildest dreams would I have thought that would happen.”

It knocked Detmers out of the game after 5 2/3 innings and 95 pitches. Catcher Logan O'Hoppe, who left in the fifth inning with a right hand contusion after being hit by a foul ball, said he believes Detmers has elite stuff, but now it’s just about figuring out ways to utilize it better.

“His stuff is good, but we’re still trying to see where we can fit the heater,” O’Hoppe said. “We can obviously lean on his slider, which is a big help. But it’s about finding and understanding his strengths and using those when needed.”