That move, predictable in its nature, will be to add Adam Eaton to the active roster. Eaton, who signed a Minor League contract with the team during Spring Training, won't be needed to start until April 12. The Orioles will take advantage of that timetable by keeping an extra infielder and an extra reliever until they need him.
"It just gives us more flexibility," said Trembley of delaying the roster move. "The day before [Eaton] pitches, when his contract is purchased, is when we'll have to make a move. What it does is just strengthen your team. It gives you another arm and another position player for the first four or five days of the season."
The players impacted most by that decision are reserve infielder Robert Andino and relievers Brian Bass and Matt Albers. Andino, who was recently acquired in a trade for Hayden Penn, would likely be the casualty if Baltimore goes with 13 pitchers. Otherwise, Bass and Albers might find themselves on the other end of the move.
Trembley wouldn't say which way he was leaning on Sunday, but the Orioles thought long and hard about adding a backup with the ability to play both shortstop and second base. Now that they've done so, they're not likely to switch gears unless they have a serious bullpen shortage at some point in the first week.
"We have some time," Trembley said. "Right now, we have that backup shortstop in Andino. We have the extra arm in the bullpen. At the end of these first four or five days, we'll see what our needs are and then go from there."
Eaton, who threw a side session on Sunday, said that the move is on paper and doesn't really affect him.
"It's a little weird, but at the same time, it helps the ballclub out," he said. "I'll still get normal work. I just can't be on the field during the game. It's a little strange in that respect, but I'll be up here spinning wheels."
Meanwhile, the backup-catching situation was a little more clear-cut. Trembley went back and forth between Moeller and Robby Hammock during Spring Training, but he eventually settled on the better defensive backstop. Moeller, who caught for the Yankees last season, just seemed like a better fit for a number of reasons.
"He has experience against teams in [the American League East]," said Trembley. "I think that will lend itself toward him making a real nice contribution to our pitching staff. Hammock is a versatile player. In Spring Training, he was more of an offensive-type player. We decided to go with Moeller because of his experience catching in this division."
That was all the news that came out of Baltimore's final preseason workout, and Trembley said he gave his players a speech in which he underlined how fortunate they were to be at this place in time. Now, there's nothing left to do except get a good night's sleep and then come back to face the Yankees on Monday at 4:05 p.m. ET.
"It's a special time of year for everyone, a new season for the Baltimore Orioles," said Trembley of Opening Day. "We're anxious to get going and to get off to a good start. We'll have a nice workout today. It won't last very long. We'll allow guys to spend some time tonight, and we'll come out here and go get them tomorrow."
Spencer Fordin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.