SEATTLE -- Four starts into his Major League career, Luis Medina continues to provide the A’s with a promising view of the pitcher he could potentially evolve into.

Though the A’s fell short against the Mariners, 3-2, on Tuesday night at T-Mobile Park, it was a loss that came in spite of another solid effort from Medina. Oakland’s No. 17 prospect tossed 5 1/3 innings, allowing three runs on five hits and two walks with four strikeouts.

“This kid is battling. He’s grinding,” A’s manager Mark Kotsay said of Medina. “He’s getting better. That’s the sign that we’re looking for. This is another really quality start, if you think about it. The long ball just seems to get him, and it gets him towards the end.”

Medina dominated early, holding Seattle’s offense to one hit through four scoreless innings. As can be the case with most young pitchers, the 24-year-old righty ran into trouble once he began his third time through the order.

After quickly retiring the first two batters of the fifth, a double by Mariners No. 9 hitter Tom Murphy was followed by back-to-back homers surrendered to J.P. Crawford and Ty France, flipping what was a 2-0 A’s lead to a 3-2 deficit. While Medina did get out of the inning, a well-struck flyout to deep center by Eugenio Suárez in the sixth was a signal to Kotsay that it was time to pull the rookie at 88 pitches.

“Every pitcher has areas of data to support that the third time through is the most difficult part to get through,” Kotsay said. “Tonight with Luis, he ended up running into that. That is part of growth. It’s part of experiencing it and being out there in that leverage situation and going through it.”

Throughout the Minor Leagues, Medina’s blazing fastball was without question his standout pitch. It was certainly in true form against the Mariners, maxing out at 99 mph and averaging 96.7 mph throughout the night.

Equally as impressive of an offering, however, was his slider. Medina threw it 27 times, generating 18 swings and nine whiffs with it. His four strikeouts -- all of which were swinging -- were finished off with the slider.

“He has the stuff,” said A’s catcher Carlos Pérez. “The velocity is there. I think, little by little, he’s gaining confidence by knowing how to pitch in certain situations. I told him tonight that I really liked how he pitched today, home runs aside.”

The highest compliment a pitcher can receive often comes from the other side, and Medina has garnered a few of those early in his big league career. On Tuesday night, it was Mariners manager Scott Servais who offered praise.

"Their starter had good stuff,” Servais said. “We knew coming in, he's a young pitcher and he's just got a really good fastball. He's got quality secondary pitches. We knew it wasn't going to be a big, high-scoring night."

The pair of home runs allowed brought Medina’s Major League total to seven over 22 1/3 innings, all this season. He’s given up at least two in three of his first four starts with the A’s, so the long ball is clearly an issue that will need to get under control. Overall, the takeaway from Medina’s first month as a big leaguer is that he is quickly shedding the notion that he may be better suited for the bullpen.

“I feel very positive in each outing I make,” Medina said in Spanish. “Every start, I go out with more hunger and desire to put the team in a position to win. I want to put the team in a good situation every time. I’m going to go out every start with even more hunger.”