BALTIMORE—After the Orioles added DJ Stewart to their major league roster, many fans wondered why they added Stewart, who had a disappointing minor league season, instead of Ryan Mountcastle, who had a superior offensive year.

Stewart and Mountcastle were the first two Oriole selections in the 2015 draft. But there’s an important difference between them. Stewart was drafted as a college player while Mountcastle was picked out of high school. College players must be protected three years after they’re drafted while high school players can escape protection until four years after their draft.

The Orioles have a need for outfielders, and Stewart, even though he hit just .235 for Norfolk, can play left field during the final weeks of the season. Mountcastle, who’s played third base and shortstop in the minors, needs to find a position where he’s comfortable, and the Orioles aren’t convinced he’s ready for the major leagues defensively.

But even if they wanted to add Mountcastle, who hit .297 with 13 home runs and 59 RBIs for Double-A Bowie and became more selective at the plate this year, they would be putting him on the 40-man roster before they have to, and this year they have a roster that’s in flux.

With the expanded roster this month, the Orioles have 34 active players, and have just three healthy players who are on the 40-man and not with the parent team: pitchers Donnie Hart and Evan Phillips and outfielder Anthony Santander. Hunter Harvey, infielder Engelb Vielma and outfielder Austin Hays are injured.

The Orioles considered adding Hays to the major league roster, but he’s having ankle surgery on Thursday. The ankle bothered him much of the season at Bowie.

Richard Bleier, Mark Trumbo and Pedro Araujo, a pitcher selected in the Rule 5 draft last December, are on the 60-day disabled list and must move back to the 40-man roster before December’s Rule 5 draft.

The team has only one pending free agent, Adam Jones, and that means that in order for the Orioles to add players to the 40-man from both within the organization and from outside it, they’ll have to drop players.

Because the team has become radically different since July, not only is there only one free agent, but there are only six players eligible for arbitration this fall: Tim Beckham, Dylan Bundy, Mychal Givens, Caleb Joseph, Jace Peterson and Jonathan Villar.

Of those, it’s possible that the Orioles non-tender Beckham, who could get perhaps $5 million in arbitration.

The Orioles have tough decisions on which players to protect this fall. Some of the top prospects that could be taken in the Rule 5 draft if not protected are pitchers Tanner Chleborad and Jay Flaa, both ticketed for the AFL; Brian Gonzalez, their top selection in 2014; Luis Gonzalez, Branden Kline and John Means. Catcher Martin Cervenka, who had a fine season at Double-A Bowie, is a likely add to the 40-man roster.

Room could be made on the roster by jettisoning some players on the active roster, but it seems likely there’ll be fewer open spots on the 40 than there have been in recent years.

Last December, the Orioles had enough openings to pick three players in the Rule 5 draft: Araujo, who must stay on the active roster 17 days next season to fulfill his Rule 5 obligations, Nestor Cortes and Jose Mesa, Jr. Cortes and Mesa were both drafted from the New York Yankees. Cortes began the season with the Orioles, but was returned by mid-April. Mesa never made it out of spring training before being sent back to New York.

Not only is the roster in flux, but so are the decision makers. The contracts of manager Buck Showalter and executive vice president of baseball operations Dan Duquette expire next month, and decisions must be made quickly about who will be in charge for 2019 and beyond.