Who should back up Ryan Mountcastle at first base?

The Orioles have dealt with a logjam at first base for years. Chris Davis, Mark Trumbo and Trey Mancini crowded the position at the end of the last decade, and Ryan Mountcastle entered the conversation in 2020.

Davis and Trumbo are long gone, and the Orioles dealt Mancini to Houston at the deadline. Suddenly, Mountcastle stands alone as the only everyday first baseman on the roster.

It may be a foreign concept in Baltimore, but plenty of teams fly with one main option at first. Still, it’s curious to see who the Orioles will use to back up Mountcastle down the stretch.

Tyler Nevin currently holds a spot on the 40-man roster, but the 25-year-old has failed to materialize as a candidate for more at bats. Fangraphs has Nevin at a -0.4 WAR with just 179 plate appearances this season. He holds a .558 OPS and has just seven starts at first this year.

Nevin has made a majority of his starts at third base this season, but his days on the active roster could be numbered. The wait for Gunnar Henderson is nearly over, and the 21-year-old would likely mark an immediate improvement at the hot corner.

The Orioles made waves last week when they had Henderson play on the right side of the infield. Henderson appeared at first and second base with Norfolk, and few struggled to connect the dots. Rougned Odor, Baltimore’s starting second baseman, entered last night’s game hitting .203.

Would the Orioles really call up a top prospect and ask him to play out of position? It seems extremely unlikely. Henderson plays shortstop and third base, and the adjustment to major league pitching would keep his plate full without a new position on the diamond.

Baltimore could ask a player already with the club to pivot. Anthony Santander has taken ground balls at first over the last month, and Brandon Hyde admitted he could use the former Rule 5 pick at first down the stretch. Santander played first in the minors during his time with Cleveland, and Hyde labeled his reps this year as a “refresher” as opposed to a lesson.

Hyde told MASN’s Roch Kubatko earlier this month that “the more positions you can play for your own personal career, the better it is.” That could be Baltimore’s thought process with Henderson. I’d imagine Mountcastle may disagree after his experience in the minors.

The Orioles have another player on the active roster who played first as a prospect. Adley Rutschman started 28 games at first base between Bowie and Norfolk in 2021. Rutschman has yet to play first at the major league level, but the 24-year-old has consistently served as the designated hitter when he is not behind the plate.

Baltimore is likely already using Rutschman more than envisioned, but the rookie has made his bat indispensable. The DH days are a form of rest, and the O’s do not need a worn out Rutschman down the stretch.

A first baseman does not require anything close to the amount of rest that a catcher needs, and Mountcastle’s splits should keep him in the lineup everyday. Does a healthy Mountcastle make the question irrelevant?

Henderson could take Nevin’s place on the roster any day now, but Nevin could return when rosters expand on September 1. The Birds could also wait to promote Henderson until September and keep Nevin on the roster for the remainder of the season.

Terrin Vavra projects as a utility player, but the rookie has yet to play first base with the organization.

Santander and Rutschman could both play the position in a pinch, which likely makes Nevin expendable in the short term. The duo would allow Baltimore enough flexibility to leave Nevin off a playoff roster if the Birds managed to make the postseason this year. Brandon Hyde is managing to win this year, so the skipper could get creative when necessary.