The Orioles announced this morning that right-hander Zach Eflin underwent a lumbar microdiscectomy procedure. The season-ending back surgery was announced last week, and this morning’s procedure went as expected, per the team. Eflin is hopeful of having a “normal” offseason after about 12 weeks, but recovery from this type of procedure can take anywhere from four to eight months. Every instance is different, of course, and there’s no real way to tell just how long Eflin will be down until he begins the rehab process.

This was a disaster season for the 31-year-old Eflin, who’s been limited to 14 starts and 71 1/3 innings by a lat strain and this back issue — an injury he revealed has bothered him on and off for several years. He posted a dismal 5.93 ERA when on the field — miles away from the 3.54 mark he posted in 343 innings for the Rays and Orioles during the first two seasons of his current three-year, $40MM contract (2023-24).

Eflin said last week that he was very open to a return to the Orioles. Whether the team pursue that option remains to be seen, but the O’s will clearly be in the market for arms this offseason. Eflin is a free agent, as is righty Tomoyuki Sugano. Fellow right-hander Charlie Morton was traded to the Tigers (and is a free agent at season’s end, too). Grayson Rodriguez won’t pitch this season after undergoing a debridement procedure in his elbow. The O’s have Trevor Rogers, Dean Kremer, Cade Povich and Brandon Young all controlled through next year. Righties Tyler Wells and Kyle Bradish can hopefully contribute down the stretch after they wrap up their rehab from last year’s UCL procedures, but a return to full health and prior levels of performance can’t simply be assumed.

Bradish, according to Roch Kubatko of MASNsports.com, is expected to make one final rehab start before he returns from what will end up being about a 14-month absence due to Tommy John surgery. He’s made five minor league starts and pitched to a 4.67 ERA with a 28.6% strikeout rate and 7.8% walk rate in 17 1/3 innings thus far. Wells, who had internal brace surgery around the same time as Bradish had his own operation, has made four rehab starts and pitched 13 innings of 2.03 ERA ball with nearly identical strikeout and walk rates to those of his teammate (28.3%, 7.5%). Bradish is controlled three more years beyond the current season. Wells is controlled for two more years.

Elsewhere on the roster, Ryan Mountcastle is facing some roster uncertainty of his own. The longtime Baltimore first baseman missed more than two months with a hamstring injury, and he returned to a very different roster. The O’s sold off veterans Morton, Cedric Mullins, Ryan O’Hearn, Ramon Laureano, Seranthony Dominguez and Gregory Soto at the trade deadline. Prospects Coby Mayo and Samuel Basallo are now getting legitimate auditions to show they can be long-term contributors at Camden Yards.

The presence of both Mayo and Basallo has and will continue to cut into Mountcastle’s playing time. The 28-year-old Mountcastle chatted with Andy Kostka of the Baltimore Banner about his reduced role, stating that he took it in stride and will be eager to help Mayo or Basallo with any questions or insight they might seek down the stretch. “Whatever they need, whatever I can do to help, I’m willing to do it,” Mountcastle said.

Interim manager Tony Mansolino told Kostka that he’ll try his best to be “creative” and get at-bats for Mayo, Basallo, Mountcastle and catcher Adley Rutschman to the extent possible. Basallo will be backing up Rutschman behind the plate but also factor in at first base and designated hitter — Mountcastle’s two positions.

From a bigger-picture standpoint, it’s increasingly fair to wonder about Mountcastile’s future outlook with the team. He’s eligible for arbitration for the final time this winter and will get a raise north of $7MM. He’ll be a free agent after the 2026 season. The O’s, as previously mentioned, are going to need to invest in the rotation this winter and, in Mayo and Basallo, now have younger pre-arbitration options to step in at first base and DH. It’s easy enough to see Mountcastle being traded or, depending on how he finishes, perhaps even non-tendered.

Mountcastle struggled tremendously prior to landing on the injured list, hitting just .246/.280/.348 in exactly 200 plate appearances before his injury. He’s had limited playing time but looked excellent upon his return. He hit .387/.486/.806 in nine rehab games (31 plate appearances) and, since returning, is 8-for-29 with two homers, a double, a pair of walks and a hit-by-pitch. He’s slashing .276/.333/.517 in his first 33 plate appearances back on the big league roster and has even stolen a pair of bases (despite stealing just three in each of the past two seasons).

So far, anyway, the hamstring looks to be rehabilitated, and Mountcastle looks far better than he did early on. It bears reminding that from 2021-24, Mountcastle was a key factor in a terrific Baltimore lineup, hitting .260/.312/.447 with 86 home runs, 102 doubles and five triples. He’s a right-handed hitter who’s beat up left-handed pitching throughout his career and turned in slightly better-than-average results versus righties. He’s also a sound defensive first baseman. With a 2026 salary likely in the vicinity of $8MM, Mountcastle could be a nice short-term pickup for a team looking for a stopgap option at first base — if the Orioles elect to go with their up-and-coming bats at the position.