The A’s expect better days ahead for Daulton Jefferies after his Major League debut.

Called up to start the first game of a seven-inning doubleheader against the Rangers on Saturday at Globe Life Field, Jefferies received a rough welcome to the big leagues in a 5-2 loss. The right-hander surrendered a pair of home runs and was tagged for a five-run first, leading to a departure after just two innings.

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Jefferies, Oakland’s No. 7 prospect and top right-handed farmhand, positioned himself for a callup last year after putting together a brilliant strikeout-to-walk ratio in the Minor Leagues, with 93 strikeouts against nine walks. So it was a bit peculiar that his downfall in the 36-pitch first was the result of two walks issued to the first four batters before a three-run shot by Rougned Odor.

Jefferies was really one strike away from avoiding the first-inning troubles, getting to a 1-2 count to No. 4 hitter Joey Gallo with two outs, before walking him and allowing all five runs on homers to Odor and Ronald Guzmán.

Was the 25-year-old Jefferies feeling the typical nerves that come with a Major League debut?

“I think so,” A’s manager Bob Melvin said, “based on the fact that he walked a couple of guys and he never walks anybody. He was probably a little amped up. The homers came on changeups thrown at a higher velocity than he normally throws them. First inning can be tough, regardless. In your first start, you give up a three-run homer, it can get to your nerves a little bit.”

In a small bit of redemption, Jefferies was able to finish his outing on a good note. The righty went back out for the second and tossed a scoreless frame, finishing his debut with five earned runs on five hits and two walks with the lone punchout over two innings.

“With his injury history, we didn’t want him throwing 40 pitches in the first,” Melvin said. “At least he gave us a couple of innings and settled down after that. He’ll be better next time.”

The early five-run hole was too much for the A’s offense to overcome. Collecting just four hits on the day, Oakland’s two runs came on Jonah Heim’s RBI single in the third and an RBI double by Matt Olson in the sixth.

In a game low on positives for the A’s, reliever Jordan Weems provided a bright spot by saving the bullpen in impressive fashion. The right-hander took over for Jefferies to begin the bottom of the third and tossed three perfect innings with five strikeouts on 38 pitches.

“That was terrific. We needed that,” Melvin said. “He really didn’t throw a ton of pitches in three innings. When you’re in a stretch like this, you’re trying to keep as many guys available as you can. Jordan saved us.”