SCOTTSDALE, Ariz. -- It’s still unclear who the D-backs’ No. 5 starter will be. But the field got a bit narrower on Sunday.

Brandon Pfaadt, ranked as Arizona’s top pitching prospect and No. 59 overall by MLB Pipeline, was reassigned to Minor League camp prior to the D-backs’ 13-2 win over the Royals at Salt River Fields. The right-hander had been in the running for the fifth starter job, along with Tommy Henry, Ryne Nelson and Drey Jameson.

Pfaadt posted a 3.75 ERA in four Cactus League appearances, with 15 strikeouts and four walks in 12 innings. Nelson has pitched to a 8.38 ERA, Jameson is at 7.45 this spring and Henry sat at 5.51 after throwing 4 2/3 scoreless innings against Kansas City.

“The thinking is that we have a lot of guys that are competing for one spot,” manager Torey Lovullo said. “[Pfaadt], of course, was given an opportunity. We loved what we saw. It was just time to get him back to the Minor Leagues, get him stretched out and get him moving in the right direction so he can prepare for the season.”

Unlike Henry, Nelson and Jameson, who all pitched for the D-backs in 2022, Pfaadt has no Major League experience.

“I think there are some other guys that have proven it at this level and are going to be looked at a little bit differently,” Lovullo said. “We love the stuff. We just felt like it was the best situation for him and his development at this point in time to go down and continue growing and learning.

“He’s going to find himself in the big leagues at some point. We just felt like it was the right move at this time.”

Martin likely out for 2023

Right-hander Corbin Martin will undergo surgery to repair a tear in the lat tendon under his right shoulder and is doubtful to return this season, Lovullo said.

“It’s going to be a long-term recovery,” said Lovullo, while adding that he didn’t know when Martin will have the procedure.

It’s the latest setback for Martin, who missed most of the 2019 season and all of ‘20, after undergoing Tommy John surgery. He’s also been on the injured list each of the last two seasons.

Martin was one of four players acquired in the trade that sent Zack Greinke to the Astros at the 2019 Trade Deadline.

Spring cuts

In addition to Pfaadt, the D-backs made 10 other roster moves.

Arizona sent infielders Seth Beer and Diego Castillo to Triple-A Reno. The club also reassigned infielder Buddy Kennedy, left-hander Jessie Biddle, right-handers Jandel Gustave, Zach McAllister, Mitchell Stumpo and catcher Dominic Miroglio to Minor League camp, along with infielder Yairo Munoz and catcher Ali Sanchez.

“Never an easy day. You get attached to these guys,” Lovullo said. “They get attached to this environment and try to make a team. You kind of put their dreams on pause. 

“They all understood. We were able to deliver good messages. They’re going to go down and continue to progress and learn and grow day by day, and get themselves back to this level.”