Mariners notebook: Kendall Graveman placed on 10-day IL

The Mariners don’t have a definitive cause for the issues in right-hander Kendall Graveman’s neck, but they know he won’t be making his next start on Saturday against the Colorado Rockies.

The Mariners placed the veteran starter on the injured list (retroactive to Aug. 3) with neck spasms on Tuesday afternoon with a handful of other roster moves that included selecting the minor-league contract of right-handed pitcher Joey Gerber and adding him to the 40-man roster and the 30-man active roster.

They also recalled left-hander Taylor Guilbeau and optioned right-hander Zac Grotz to the team’s alternate training site in Tacoma.

The Mariners are still trying to find out the cause of Graveman’s neck spasms.

“He’s getting more tests done (Tuesday),” Mariners manager Scott Servais said. “We’re waiting to get more results back now. He had a different scan done today and has talked to a number of different doctors, trying to figure out what the right treatment to go toward to try to clean this up and calm it down as quick as possible.”

With Graveman out, the Mariners prefer to maintain their six-man rotation and will likely slide lefty Nick Margevicius into Graveman’s spot, joining Marco Gonzales, Taijuan Walker, Yusei Kikuchi, Justus Sheffield and Justin Dunn.

“I do like the six-man rotation,” Servais said. “I think it’s been beneficial for those guys. Certainly with Marco, Yusei and Taijuan, allowing them to go a little bit deeper and also giving our young guys that extra day before they go out there again.”

Gerber, 23, is rated as the No. 25 prospect in the Mariners organization by Baseball America. He was impressive during the original spring training, making five appearances and not allowing a run in five innings pitched with a walk and seven strikeouts. Gerber, an eighth-round pick in the 2018 draft out of the University of Illinois, split last season between High-A Modesto and Double-A Arkansas. In 19 appearances with Arkansas, he posted a 1.59 ERA with 30 strikeouts and seven walks in 22⅔ innings pitched.

Guilbeau gives the Mariners another lefty to use with Margevicius entering the rotation, while Grotz returns to Tacoma to find some command that evaded him; he had seven walks in six innings pitched.