OAKLAND -- Mason Miller's rapid ascent into budding stardom will have to take an extended pause, though the ultimate diagnosis regarding his elbow issue aligns with what the A’s were expecting.

After receiving a second opinion from Dr. Keith Meister in Dallas, Texas, on Tuesday, Miller, Oakland’s No. 3 prospect and the No. 97 prospect in baseball per MLB Pipeline, was diagnosed with a sprained ulnar collateral ligament in his right elbow. The A’s had originally diagnosed the right-hander with right forearm tightness following his outing on May 7 against the Royals in Kansas City.

Miller remains on the 15-day injured list. He will clearly be unable to return when eligible on May 23. Still, the A’s see a path for the 24-year-old flamethrower to pitch again this season.

“All indications point that this will heal and he’ll have a good outcome,” A’s director of sports medicine and rehabilitation Brian Schulman said prior to Tuesday’s game against the D-backs. “We’re not really concerned with the long-term future at all. Just get through this little hump in the road and get him back out here when he’s safe.”

The A’s plan to keep holding Miller out of all throwing activities until he is fully asymptomatic. As of now, he continues to experience soreness in the area, and there is no timetable for a return until he can pass all medical tests put together by Oakland’s training staff.

“Very mild,” Schulman said of the UCL sprain. “Basically, [the test results] just showed a little bit of inflammation around the ligament. We’re going to follow a conservative plan of care.”

Miller has been nothing short of electric since receiving his first call to the big leagues this season. Through his first four Major League starts, Oakland’s top pitching prospect holds a 3.38 ERA with 22 strikeouts in 21 1/3 innings. His brilliance was on full display on May 2, when he tossed seven hitless innings against the Mariners at the Coliseum.