PEORIA, Ariz. -- Add George Kirby to the list of Mariners pitching prospects that have recently reported to big league Spring Training as a non-roster invite.

Kirby, the club’s No. 6 prospect and MLB Pipeline’s No. 92 overall, on Wednesday joined Emerson Hancock and Brandon Williamson, who reported last week. Like those two, Kirby will play catch and work out, but he will not play in Cactus League games. The Mariners are now up to 73 players in camp, and they likely won’t make many, if any, cuts until the very end.

The Mariners won’t begin stretching Kirby and the others out until Minor League camp begins after the big leaguers depart for Opening Day on April 1. This is merely the opportunity to utilize the vacant roster space to bring their young arms along and have them spend time with the Major League pitching staff.

“They get a feel for it in big league camp and some of the discussions, whether you're in a throwing program with Marco [Gonzales] or [Kendall] Graveman, or guys like that, you kind of watch how they do it and learn,” manager Scott Servais said. “You learn from other players, and sometimes it's not all the meetings. We can't have a lot of meetings here. So, it's the conversations you're having out on the field.”

Kirby, like Hancock and Williamson, spent all of the 2020 regular season at the alternate training site. He’s touted to have among the best control of any pitcher in the Minors. Kirby topped out at Class A (short season) Everett in his first stint with the Mariners after being drafted. He’s destined to begin the Minor League regular season at a lower-level affiliate, and MLB Pipeline scouting reports list Kirby’s MLB ETA as 2023.

Kelenic injury update

Star outfield prospect Jarred Kelenic returned to the field on Wednesday for light work, but MLB Pipeline's No. 4 overall prospect isn’t running, hitting or resuming baseball activities yet. He’s also done therapy in a pool with Mariners trainers.

“I’m really happy with how he is progressing. … He’s moving in the right direction, and I know he wants to move as fast as he can,” Servais said.

Kelenic has been out since last Friday after sustaining an adductor strain in his left knee while legging out an infield dribbler against the White Sox. His recovery process before returning to game action is likely a matter of weeks.

Servais open to diversifying leadoff role

J.P. Crawford was the everyday leadoff hitter in 2020, but Servais said the return of Mitch Haniger could also make him an option. Crawford is left-handed and Haniger is a righty. If righty-hitting Dylan Moore hits the way he did at times last season, he would also be considered.

“We’ll continue to play with that. It won't be just locked in,” Servais said. “Last year, we had J.P. at the top, just because I thought we didn't have a ton of options. We were learning about a lot of our guys. The one thing about J.P. is he’s unbelievably competitive. There are times where he’s swinging the bat better than other times, but you're always going to get a good at-bat, and he makes really good swing decisions along the way. So, we'll continue to be flexible and move it around there.”

Crawford was in the one-hole for 48 of his 53 starts in 2020, hitting .250/.322/.314 with six doubles and two homers. He enjoys leading off, but he admitted that he needs to bolster his extra-base-hit ability to be more effective there.

• Stronger Crawford looks to improve hitting

Haniger was moved to leadoff for the final two months of his All-Star season in 2018 and had huge success, hitting .330/.388/.580 with eight homers, 19 doubles and two triples in 45 games. He’s slightly faster than Crawford by Statcast’s sprint speed metric.

But this roster looks drastically different from the last time Haniger hit first. Back then, he had high-end run producers Jean Segura, Robinson Canó and Nelson Cruz immediately following him. It’s Haniger who will be depended on for a huge chunk of run production in 2021.

“That's the one nice thing about this team is we do have options,” Servais said. “I love having [Haniger] back. He can really hit anywhere from one to five in your lineup. You know you're going to get a good at-bat from him.”

Sheff struggles

Justus Sheffield’s second outing of Spring Training was not nearly as clean as his first. In Wednesday’s 17-5 loss to the Rangers in seven innings, the left-hander gave up six runs, including two homers, and three walks while reaching his pitch count before his three-inning threshold.

The Mariners scored four runs in the third inning, thanks to doubles by Julio Rodríguez, Haniger and Tom Murphy. Other than that, it was a quiet offensive day. The teams didn’t play the final half inning.