Cubs — a man down in ’pen after releasing Justin Grimm — have decision to make

MESA, Ariz. — The morning after the Cubs released veteran reliever Justin Grimm, 25-year-old Dillon Maples spoke quietly at his locker about the possibility of filling the only vacancy in the team’s bullpen.

“I’m just trying to go day by day, the same approach as last year, and I’m sticking with that,” he said. “I know if I continue to stay with that approach, I’ll be in a good spot.”

No more than three hours later, Maples was informed that he’d been optioned to Class AAA Iowa, along with outfielder Mark Zagunis, trimming the spring roster to 37.

That takes a very promising young pitcher, who was a September call-up in 2017 — and in

Class A ball the year before that — out of the equation for now. Fans at Wrigley Field will have to wait to get another look at Maples’ “outrageously good” stuff, as manager Joe Maddon put it.

“It’s going to happen,” Maddon said. “He’s going to be here for a long time. He’s still learning his craft.”

So, who’s No. 8?

Lefty Randy Rosario, only 23 but with a taste of big-league experience last season with the Twins, has been impressive. So has righty Justin Hancock, who is 27 and in his eighth season of pro ball, all in the minors.

“I’m not too worried about it,” Hancock said. “If it’s my time, it’s my time.”

Hancock was an unknown to Maddon before camp, but the manager has taken notice.

“He’s got a lightning bolt for an arm,” Maddon said. “This guy is really intriguing to me.”

Another option is Eddie Butler, who made 11 starts for the Cubs last season and could offer them something along the lines of Mike Montgomery-style flexibility from the right side.

Meanwhile, Grimm is missed already inside the Cubs’ clubhouse. Maples said Grimm was the teammate who went out of his way to make him comfortable after his call-up. Maddon called Grimm a “great guy.”

Pedro Strop was bummed about not only Grimm’s departure, but also Hector Rondon’s. Those were Strop’s guys. He called Grimm’s release “tough” news.

“Every time I got here,” Strop said, “I looked to his locker. I’m always screaming at him. It became part of my routine.

“That’s two big pieces I’ve seen leaving, Rondon and him, my two buddies. It’s not easy, but I also know this is a business and this is the way it goes. And hopefully not, but one time it’s going to be me. I mean, hopefully not. I wish to retire here whenever I’m done playing. But it’s a business.”

Will it be Rosario who claims that final bullpen spot? Hancock? Butler? Someone else — maybe even free agent Greg Holland, who’s still out there and available?

Whoever it is will join a bullpen that appears to be otherwise stacked.

“It can be as good as anyone’s,” Strop said. “If you look at the 30 teams and see who have the best bullpens, you’ve got to include the Cubs, man.”

Follow me on Twitter @SLGreenberg.

Email: sgreenberg@suntimes.com