FORT MYERS, Fla. — Before the assembled press could whip out their smartphones and post the news all over social media, Colton Cowser had a request.

“Could you hold off for a little so I can call my parents?” the Orioles rookie outfielder asked. So we waited until Cowser was on the phone, informing the people who mean the most to him that he would be getting on a flight to Baltimore.

Cowser had made the Orioles’ opening day roster.

“Was I supposed to say that?” Cowser asked the public relations director standing nearby. “I didn’t know if it was supposed to be, like ...”

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A secret? Nope. Cowser’s good.

“That was on the back of my mind probably the whole day today,” Cowser said. “I’m going to soak it in, and I’m going to do whatever it takes to stay up there.”

Shortly after Cowser announced his own news, a source with direct knowledge of the situation said outfielder Ryan McKenna and infielder Nick Maton would not make Baltimore’s roster. The Orioles will have to designate both players for assignment, opening them up to be claimed off waivers by another team. If they go unclaimed, the Orioles can outright them to the minor leagues.

In addition, the Orioles announced right-hander Jonathan Heasley was optioned to the minors.

With the flurry of moves after Baltimore’s final spring training game, the opening day roster is coming into a more clear picture. Utilityman Tyler Nevin stands to be the final position player to make the squad unless Baltimore looks externally for reinforcements. The eight-man bullpen is set unless the Orioles make a similar addition from outside.

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  • That bullpen, as it stands: Craig Kimbrel, Yennier Cano, Danny Coulombe, Cionel Pérez, Jacob Webb, Mike Baumannn, Keegan Akin and Dillon Tate.
  • The position players, as things stand: Cowser, Nevin, Adley Rutschman, James McCann, Ryan Mountcastle, Ryan O’Hearn, Ramón Urías, Jordan Westburg, Gunnar Henderson, Jorge Mateo, Cedric Mullins, Austin Hays and Anthony Santander.
  • The rotation: Corbin Burnes, Grayson Rodriguez, Dean Kremer, Tyler Wells and Cole Irvin.

Cowser impressed this spring with a .304 average and 1.135 on-base-plus-slugging percentage. He clubbed six homers, and even though he finished on a 3-for-23 stretch, his overall approach was strong.

“I came out of the gates swinging really well,” Cowser said. “Then it got to the point that, because I was hitting well, I felt like I could hit everything and started to swing at a lot of pitches. I think, you know, today I struck out a couple times, but toward the end there it felt like I started to really fine-tune the approach and really started feeling better.”

Cowser made his major league debut last season and struggled in a small sample. He was pulled up midseason for a pennant race and hit .115 in 26 games, then returned to Triple-A Norfolk. He feels that experience can help him this go-around, because he now knows what to expect.

The 24-year-old’s strong performances in camp helped solidify his return.

“Colton’s really improved his standing with anyone that’s watched him,” general manager Mike Elias said this week, “but it’s nothing out of character for the talent that he’s been this whole time.”

Maton’s exclusion from the roster comes as little surprise; he went hitless in 23 at-bats. McKenna, however, has served as Baltimore’s fourth outfielder for much of the past three season. He has a career .203 average in the majors. It remains to be seen whether he can sneak through waivers to remain in the organization.