ARLINGTON -- When the A’s look back on this rebuilding campaign, Luis Medina will stand out as one of the more positive developments. Entering 2023 having never pitched above Double-A, the right-hander has emerged as a Major League starter with spurts of looking downright electric at times. 

Like most rookies on this team, though, Medina has also taken his share of lumps. Sunday was an example of that.

In Oakland’s 9-4 loss to the Rangers at Globe Life Field, a leadoff home run surrendered to Marcus Semien set the tone in what quickly became a rough one for Medina. Over 4 1/3 innings, the 24-year-old allowed five runs on six hits and three walks with three strikeouts.

“These are the road bumps we’re talking about,” A’s manager Mark Kotsay said. “[Medina] comes out in the first and gives up three runs. He bounced back from the second through fourth. Then that fifth inning, a couple of walks and it gets out of control for him. That’s the experience we need to get him built up. He’s got to go through that.”

Medina’s inability to escape a fifth-inning jam negated the lead he was handed earlier via a four-run third by the A’s offense that was sparked by rookie Tyler Soderstrom’s third career home run.

Going from playing one American League West contender to another with a three-game series against the Astros in Houston on the horizon, here are some takeaways from the series finale in Arlington:

Outfield execution
Sunday’s theme of growing pains carried over on defense. In that rocky first inning, rookie Lawrence Butler -- who was making his 17th career start in center field -- took a bad route on a fly ball struck by Robbie Grossman that ended up sailing over his head for a ground-rule double that scored two runs.

Butler, rated Oakland’s No. 3 prospect by MLB Pipeline, evolved into a well-rounded center fielder in the Minors over the past couple of years. Sunday’s misplayed ball, however, magnified an area that needs improvement.

“He’s got to get comfortable taking off and going to the spot,” said Kotsay, who had Butler watch highlights of 10-time Gold Glove-winning center fielder Andruw Jones on Friday. “That comes with time. We’re going to work hard on getting him comfortable doing that.”

Soderstrom’s much-needed blast
Having just graduated from his status as the A’s No. 1 prospect, Soderstom has experienced the euphoria of barreling up plenty of balls. So far in his big league career, though, it would be hard to find a better feeling than the one on the first-pitch curveball from Jon Gray he swatted into the right-field seats for a 381-foot solo shot, as projected by Statcast.

Prior to the homer, Soderstrom had not reached base in a game for the A’s since Aug. 18. Over that span, he was optioned to Triple-A for a chance to regroup after a rough start at the plate.

“The lack of success offensively, you can see it kind of wearing on him,” Kotsay said. “He came in yesterday and we talked for a while. You’re not always going to come up and have success. To see him take a good swing on that first pitch and drive it out the ballpark is a good sign.”

Through 31 Major League games, Soderstrom is batting .158 with a .494 OPS, a far cry from his career .856 OPS over three Minor League seasons that helped him skyrocket through the system and reach the Majors in July as a 21-year-old.

“I just have to stay confident,” Soderstrom said. “Learn to be confident all the time, no matter if it’s going bad or good. That’s the biggest thing I’ve got to work on. Keep my confidence. I know I’m a great player and I know I’m going to play in this league for a long time.”

Gelof going off
Sunday marked Zack Gelof’s 50th MLB game, and what a ride it has been.

Fresh off earning AL Rookie of the Month honors in what was his first full month as a big leaguer, Gelof is building an early case to repeat. Entering Sunday, the second baseman was hitting .353/.405/.559 with five extra-base hits in eight September games.

Overall, Gelof’s 28 extra-base hits are the most by any A’s player over their first 50 career games in franchise history.

“Had he started out with us at the beginning of the year, maybe he’s in serious talks about Rookie of the Year,” Kotsay said. “This kid has done everything possible since he’s been with us. We’ve talked about setting records. … We look forward to him for, hopefully, many years.”