The Mariners have announced that lefty Drew Smyly will undergo Tommy John surgery for a torn ulnar collateral ligament. He is expected to miss the standard twelve to fifteen months in recovery.

That’s obviously devastating news for the 28-year-old southpaw, who had been hoping to work back from elbow issues that have put him on the shelf all year. He had shown quite well in the World Baseball Classic, with enhanced velocity, leading to hopes for a big first season in Seattle.

Instead, it now seems possible that Smyly won’t ever make an appearance for the M’s, who traded Mallex Smith and others to acquire his rights over the winter. Smith had been added earlier that day in a clearly related swap that sent pitching prospect Luiz Gohara to the Braves.

Smyly is earning $6.85MM this year and would command the same through arbitration in 2018 — his final trip through the process. It’s still possible that Seattle could attempt to work out some kind of arrangement to keep him in the organization for the future, but it obviously makes little sense for the team to pay him a significant salary for a year that will be spent rehabbing.

Last year was a rough one for the southpaw, who scuffled to a 4.88 ERA over 175 1/3 innings, though it also represented his first thirty-start campaign in the big leagues. He also still managed a healthy 8.6 K/9 against 2.5 B/9, with 32 home runs and a below-average 67.7% strand rate contributing to the ugly results.

Given his age, Smyly still has a shot at returning for many more years of pitching. Of course, he’ll need not only to work back from the UCL replacement, but also to find a way to avoid future elbow problems. (He had been among the highest-risk players identified by MLBTR contributor Bradley Woodrum in a 2016 study, and the risks for another will only increase.)

For the Mariners, the news confirms what the club surely already feared: there won’t be a reinforcement coming to the team in 2017. With Felix Hernandez and Hisashi Iwakuma showing their age, and James Paxton coming back down to earth of late, there are questions at the front of the staff.

There are depth concerns, too. While Sam Gaviglio owns a 3.38 ERA through 45 1/3 innings, the metrics don’t like his chances to maintain that performance. Similarly, Ariel Miranda has been solid but is benefiting from a likely-unsustainable .226 BABIP. It’s anyone’s guess what the team can hope to receive from Andrew Moore and others.

The fact that there’s a potential need doesn’t mean that the M’s can afford to go out and add a top-line starter, of course. Several quality arms could be available, of course, but there’ll be competition and steep asking prices. While Seattle has positioned itself as a win-now organization, it’s also a notable consideration that the AL West seems out of reach, meaning any present-focused moves come with the likely upside of earning a Wild Card berth.

Mariners left-hander Drew Smyly has been diagnosed with a flexor strain in his left arm and will miss the first six to eight weeks of the regular season, tweets Bob Dutton of the Tacoma News Tribune. In his place, left-hander Ariel Miranda will step into the Seattle rotation and start the team’s fourth game of the year, Dutton adds.

Ryan Divish of the Seattle Times notes that Seattle doesn’t think surgery will ultimately be necessary for Smyly, but the left-hander will head out for second and third opinions on the injury from different doctors in order to be sure (Twitter links).

The loss is, obviously, a dreadful blow for the Mariners to suffer so close to Opening Day. Smyly was utterly dominant when pitching for Team USA in the World Baseball Classic and was expected to play a significant role in the Mariners’ rotation in 2017.

While he’s coming off a dismal 4.88 ERA in 175 1/3 innings with the Rays last season, Smyly averaged 8.6 strikeouts and just 2.5 walks per nine innings pitched in that time as well. He’s demonstrated improved strikeout and walk rates with Tampa Bay over the past two seasons and, as an extreme fly-ball pitcher moving to the spacious Safeco Field with what looks to be a terrific outfield defense, was viewed by many (myself included) as a potential breakout candidate this year.

With Smyly on the shelf, the Mariners’ rotation will consist of Felix Hernandez, Hisashi Iwakuma, James Paxton, Miranda and offseason acquisition Yovani Gallardo (who, like Smyly, is hoping for a rebound campaign in his new environs). Seattle picked up Miranda in the trade that sent Wade Miley to the Orioles last season, and Miranda enjoyed success down the stretch with the M’s (3.88 ERA in 58 innings — albeit with less-encourgaing peripheral stats). As such, they won’t be plugging a complete unknown into the starting five, but Miranda is nonetheless a step down in terms of what can be reasonably expected out of that rotation slot.

Miranda is hardly the only depth option the Mariners have, however. On the contrary, GM Jerry Dipoto made a point of adding a number of starters with big league experience to the 40-man roster this winter, picking up Dillon Overton, Rob Whalen and Chris Heston on the trade market. Should Miranda falter, or should another starter fall to an injury, any of that bunch could conceivably step into the Seattle rotation as well.