ANAHEIM -- The A’s will be without one of their long-relief options as rookie right-hander Daulton Jefferies was placed on the 10-day injured list with right elbow ulnar neuritis on Saturday. Jefferies will be reevaluated in the coming days.

Jefferies, Oakland's No. 5 prospect according to MLB Pipeline, was scheduled to make his third career start on Saturday against the Angels as he looked to begin to acclimate to the Majors over since being recalled from Triple-A Las Vegas on Aug. 27.

A’s manager Bob Melvin said Jefferies was dealing with nerve irritation for a few days following his last outing on Sept. 12. Melvin also said the club believes Jefferies’ injury does not appear to be a ligament issue, but it is rather an irritation issue in a nerve.

“For a young guy, [he was] probably a little hesitant to bring something like that up,” Melvin said. “But it came to a point where he needed to, and I'm glad he did. We certainly don't want to push a youngster into going out there and doing something that potentially could set him back for a while.”

Jefferies logged 15 innings and had a 3.60 ERA and a 1.00 WHIP in 2021 in five appearances (one coming as a starter, on Aug. 1 against the Angels).

The 26-year-old threw five innings, gave up three runs and earned his first career win in that lone start. From the bullpen, he had completed 10 innings and allowed three runs over four September appearances.

• Jefferies embracing 'pen role, 'happy to help'

“We'll see where we go with this,” Melvin said on Jefferies’ timetable for a return. “Unfortunately, he was looking forward to his start [on Saturday], but that's not going to happen and we'll proceed accordingly to see how he feels in the next few days.”

Jefferies’ IL stint is retroactive to Sept. 13. Lefty Sam Moll was recalled from Triple-A Las Vegas on Saturday to take his roster spot.