MESA, Ariz. -- The qualities are there for Mason Miller to one day reign as ace of the staff for the A¡¯s.

For at least the 2024 season, though, Miller will be taking his electric arsenal of pitches to the bullpen. As the A¡¯s opened up Spring Training for pitchers and catchers this week, Miller reported to camp with his name listed among the club¡¯s group of relievers.

After Miller spent four months on the injured list last season due to an ulnar collateral ligament sprain in his right elbow, the A¡¯s took an ultra-cautious approach upon his return in September. Keeping him on a strict limit of no more than 54 pitches over his final six outings, the rookie finished the season healthy, posting a 3.78 ERA in 10 games (six starts) with 38 strikeouts and 16 walks across 33 1/3 innings.

That type of workload from September is likely to continue for Miller. Tossing his first bullpen session of the spring on Thursday at Hohokam Stadium, the 25-year-old right-hander was once again lighting up the radar gun with his fastball that averaged 98.3 mph last season. It was a successful first step in the A¡¯s mission to get Miller through the next five weeks and into the regular season free of injury.

¡°The biggest goal for us is to get Mason Miller out of this camp healthy,¡± A¡¯s manager Mark Kotsay said. ¡°That¡¯s our focus. We¡¯ll prepare him as a reliever. He¡¯s a guy that can throw two or three innings. But I think [in Spring Training], we¡¯ll probably see him in two-inning stints, at most, towards the end.¡±

Given his injury history, Miller is fully on board with shifting to the bullpen this year. The transition is something he took into account while working out back home in Pennsylvania during a busy offseason that also saw him get married.

¡°The preparation and the mindset changes a little bit going for shorter outings,¡± said Miller, who is ranked Oakland¡¯s No. 2 prospect and its top overall pitching prospect by MLB Pipeline. ¡°It¡¯s about getting your body in a place where it¡¯s ready every day, or every two days, as opposed to every fifth day. I¡¯m excited about it. It gives me a unique opportunity to impact the game on a more consistent basis. If it keeps me on the field, then it¡¯s definitely the right call.¡±

Oftentimes when a starter moves into a relief role, he enjoys an uptick in velocity as a benefit of pitching in shorter stints.

Could Miller, whose blazing fastball maxed out at 102.5 mph last season, somehow throw even harder?

¡°It¡¯s hard to say,¡± Miller said. ¡°I think I¡¯m a low-motor guy, so I don¡¯t know how much it¡¯s going to change. But if I can squeeze out another mile per hour or two, that wouldn¡¯t hurt, for sure.¡±

Featuring a wipeout slider, a cutter and a changeup in addition to the heater, along with good command, Miller naturally seems to fit the role of a potential closer, a role that is currently vacant with the A¡¯s. Speaking with reporters earlier this month, A¡¯s general manager David Forst mentioned Miller along with Dany Jim¨¦nez and newcomer Trevor Gott as relievers coming into spring who could get an opportunity to close games this season.

Asked about the possibility on Thursday, Kotsay indicated that he would like to see Miller succeed in high-leverage spots and gradually move up the ladder rather than anoint him as closer from Day 1.

Pitching in tight situations and recording the final out of A¡¯s victories is certainly intriguing to Miller. But whether it be starting, closing or anything in between, Miller embraces whatever title comes his way, as long as it involves pitching in the Majors this season.

¡°Playing in the big leagues is the dream,¡± Miller said. ¡°But to be able to compete for a role at the back-end [of the bullpen] like that, it¡¯s something I¡¯m excited about.¡±