BALTIMORE—In eight days, the Orioles and the other major league teams can expand their rosters from 25 to 40. Manager Brandon Hyde has said he’s not in favor of gross roster expansion, so don’t expect the Orioles to add the full 15 players.

This is the final season teams will be able to add large numbers of players on September 1. Next year, teams will carry 26 players from Opening Day until August 31, then be allowed to add two players for the final weeks of the season.

Some of the additions to the Orioles’ roster are easy. They optioned Dwight Smith Jr. to Triple-A Norfolk on Thursday. Smith was rehabbing a left calf injury with the Tides, and he’s eligible for recall in 10 days, which works out to September 1.

Mark Trumbo, who’s scheduled to begin a rehab assignment with the Tides on Tuesday, will be activated when the rosters expand, if he feels his right knee is stable. Trumbo is on the 60-day injured list, and room will have to be made on the 40-man roster for him.

Shawn Armstrong, who’s on the 10-day injured list with a strained right forearm, says the injury is minor and expects to begin throwing early next week. He’s eligible to return on September 1.

Ty Blach, who was optioned to Norfolk after Friday night’s game, will return, Hyde said on Saturday. With off days before and after the series with the Washington Nationals that begins Tuesday, the Orioles won’t need a fifth starter until September 3, when Blach is eligible to return.

The Orioles will add a third catcher, and Austin Wynns, who’s on the 40-man roster, is the likely choice.

Assuming Armstrong, Blach Smith, Trumbo and Wynns are added, that would make 30 players, and the Orioles will probably add a handful of others.

Hyde would like an additional bullpen arm or two. There are a number of pitchers at Norfolk: Tom Eshelman, David Hess, Branden Kline, Evan Phillips, Tanner Scott and Tayler Scott, who’ve all pitched for the Orioles in recent weeks, and are on the 40-man roster Expect another arm or two from that list.

If the Orioles wanted to add left-hander Keegan Akin, who’ll be included on the 40-man roster this winter, they’d have to find room there now.

The most interesting potential adds come from position players. Outfielder Austin Hays has missed time with injuries this season, and the Orioles would like to see more of him. He’s batting .250 with nine home runs and 24 RBIs in 49 games with Norfolk.

The Orioles don’t have a true centerfielder, and they’d like to see how well Hays plays center.

Cedric Mullins, who began the season in center field, had an awful month, hitting .094 (6-for-64), then was demoted to Norfolk, where he hit just .205, and to Double-A Bowie.

Mullins has .259 for the Baysox but has stolen 17 bases in 18 attempts, and it wouldn’t be a surprise to see him added as a pinch-runner since he remains on the 40-man roster.

There are no minor league infielders on the 40-man roster, so if the Orioles wanted to add Christopher Bostick, who’s played creditably for Norfolk, they must find space for him on the 40.

The most intriguing possibility is Ryan Mountcastle, who’s played 18 games in left field after playing first base for Norfolk. The power prospect, who isn’t on the 40-man roster and must be placed there before the Winter Meetings, is hitting .311 with 24 homers and 77 RBIs, but has walked just 21 times.

Mountcastle’s on-base percentage is .343, but he’s slugging a robust .528 for an .871 OPS.

Hyde’s proclamation that playing time for Chris Davis would be reduced in September increased speculation that Mountcastle would be summoned next month.

Eades gets a call: The Orioles recalled right-hander Ryan Eades from Norfolk to replace Blach on the roster.

Eades was claimed off waivers from Minnesota on August 14. He pitched 3 2/3 scoreless innings for the Twins earlier this year, and pitched 1 2/3 scoreless innings for Norfolk.

“It was a little bit of a surprise,” Eades said of the move. “Things happen quick in baseball. The manager called me in and told me what was going on, that I was going to be joining the Orioles. I talked to those guys and everyone in Norfolk and then got an opportunity to come here. I’m happy to be here and I’m going to try to help the team anyway I can.”

Eades would be the 55th player and 38th pitcher used by the Orioles. A franchise-record 56 players were used  in 2018.

The Orioles have 12 pitchers and four bench players. With two games at Nationals Park next week and no designated hitter, Hyde will have a five-man bench, if no changes are made to the roster’s composition.