The Dodgers’ 2018 season has already seen its share of insult and injury, but Monday brought the coup de grâce: Corey Seager will miss the remainder of the year due to Tommy John surgery on his right elbow. His loss means that the defending NL champions, who have limped through March and April with a 12-16 record, will never get a chance to field their best lineup, with Seager alongside third baseman Justin Turner, who’s been sidelined by a broken left wrist since March 19.

Seager has had elbow problems since late August of last season, when inflammation limited him to pinch-hitting duty during an 11-game span that was part of the team’s dreadful 1-16 tailspin. Though he said that the injury bothered him more while throwing than while batting, he struggled at the plate for the remainder of the season and into the postseason; his absence from the team’s NLCS roster was due to a back strain, not the elbow. In the wake of an MRI taken at the beginning of the offseason, TJ surgery wasn’t considered as an option, and Seager spent the winter working on rehabbing and strengthening the elbow. He didn’t play shortstop in a spring-training game until March 7.

Seager aggravated his elbow making a pair of relay throws in a loss to the Giants, and an MRI taken on Monday revealed “a much worse” injury than before. “There was no gray area as to what the right decision was,” he told reporters. Given the typical nine- to 12-month rehab period for a position player undergoing TJ, Seager might have missed the entire 2018 season anyway if his November MRI had been more conclusive.

Seager started the 2018 season slowly, going just 10-for-51 with a homer over the Dodgers’ first 12 games, but lately his bat had come to life; he’d hit .340/.424/.540 in 59 PA over their past 14, the last six of which each included a hit. The Dodgers went just 1-5 in those games, however, slipping back below .500 after clawing their way above it. Despite outscoring opponents by 12 runs, the team entered Monday three games below .500 and seven games behind the first-place Diamondbacks. Their problems have been more on the run-prevention side than the run-scoring one: they’re yielding 4.43 per game (16th in the majors) while scoring 4.75 (10th), but that’s just one more reason why the loss of the 24-year-old two-time All-Star is such a devastating blow. Seager’s 15.5 UZR over the last two seasons ranks sixth at the position, and over that span, he’s been the game’s most valuable shortstop and fifth-most valuable player according to WAR:

While the Dodgers pride themselves on depth, there’s no easy way to replace a six-win player, particularly at a time when LA’s roster is already stretched thin by injuries. In addition to Turner, the lineup is currently without second baseman Logan Forsythe, who hit the disabled list on April 15 due to shoulder inflammation, and right fielder Yasiel Puig, who landed on the DL on Sunday after fouling a ball off his left foot (bruise, no fracture).

Internally, the Dodgers’ top option to play shortstop in Seager’s absence is Chris Taylor, who had started 25 of the team’s first 27 games in center field plus one at second base. A utilityman-turned-breakout player last year (21 homers, 126 wRC+, 4.8 WAR), Taylor entered Monday hitting .233/.273/.425 with four homers and a 92 wRC+, though he’d been hotter (114 wRC+) over the past two weeks. In 96 major-league games at shortstop, he’s been a hair above average (+1 UZR, +3 DRS). Kiké Hernandez, who had hit .254/.347/.476 with three homers and a 125 wRC+ through Monday, has done well within the small sample of 51 games at shortstop (+4 UZR, +8 UZR), but he appears more likely to take Taylor’s place in center field, with hot-hitting Matt Kemp (146 wRC+), Joc Pederson (140 wRC+), and rookie Alex Verdugo getting the bulk of the corner-outfield duty in Puig’s absence. Utilityman Breyvic Valera, a 26-year-old Venezulean who was recalled from Oklahoma City to take Seager’s roster spot, has 125 games of shortstop experience spread over eight minor-league seasons, but just four games there since the end of 2016.

General manager Farhan Zaidi acknowledged that the team could eventually look outside the organization to cover for Seager’s absence — and, of course, Manny Machado’s name came up. The Orioles entered Monday 8-20 and have no chance at re-signing the 25-year-old Machado, a pending free agent who’s in his first full season back at his natural position since reaching the majors in 2012. However inevitable a trade of Machado might be, it’s difficult to see the Dodgers acquiring him. Not only would they likely have to part with blue-chip prospects such as Verdugo and righty Walker Buehler for a short-term rental, but Machado’s $16 million salary would push them back over the $197 million competitive-balance tax threshold (they’re at $181.5 million (including benefits but not performance bonuses) according to Cot’s Contracts). That, in turn, would make whatever they do this coming winter, such as re-signing Clayton Kershaw (if he opts out) or pursuing Bryce Harper, much more costly, because as repeat offenders, their marginal tax rate would be 50% for every dollar over the threshold instead of 20%.

Among other potential free-agent shortstops, many of them — such as Alcides Escobar, Freddy Galvis, Adeiny Hechavarria, Jose Iglesias, Jose Reyes — are too light-hitting to rate as improvement on the in-house options, and the last of those has a domestic-violence rap against him as well. Elvis Andrus, who can opt out of the final four years and $58 million of his contract, is on the disabled list and has a $15 million AAV. Guys like Asdrubal Cabrera, Marwin Gonzalez, and Eduardo Nunez, who are no longer shortstops anyway, are playing for contenders, as is Eduardo Escobar. Jordy Mercer, owner of a career 88 wRC+, might fit the bill if the Pirates fade from their 17-12 start. More likely, Zaidi and club president Andrew Friedman will have to get creative if they’re to make a big move, and given the state of the rest of the roster, they may have bigger priorities.

As for Seager, in the long range he’ll probably be fine. The Tommy John Surgery Database lists just 15 major-league infielders as having undergone the procedure, ranging from Hall of Famer Paul Molitor in 1984 to T.J. Rivera last September. All but Rivera, who’s still recovering, and the legendary Erubiel Durazo (sigh) returned to the majors eventually; Durazo, a fringe major leaguer by the time he had the surgery in 2005, continued to mash in the minors and Mexico. For three of the others, the actual date of the surgery is unknown, and for one of those for whom it is (Zack Cozart), the surgery was on his non-throwing elbow. That leaves this set of comparables:

That’s not a lot of recent history — one player in the past eight years — but the average return time is just under 10 months, which for Seager would be during spring training of next year. The only two players from that list who took longer than a year were well into their mid-30s. Among players in the high minors who have known surgical dates on their throwing elbows and returned to that level — a set of constraints that reduces the sample size to four — the results run the gamut from Tyler Saladino (surgery 2014, eight months to return) to Miguel Sano (surgery 2014, 13 months), with the latter’s return time lengthened by the start of the season. Gleyber Torres, who was back in action after 10 months, had surgery on his non-throwing elbow.

The Dodgers can look to Seager for next year, but for the reeling squad, they’ll need multiple players to step up if they’re to right the ship and claim a sixth straight NL West title. The team began the year with an 85.2% chance at doing so, and a 94.0% chance of making the playoffs according to our preseason Playoff Odds, but by Monday, those numbers were down to 56.8% and 75.6%, and with the loss of Monday night’s game and their shortstop, they’ve fallen to 51.5% and 72.2%. Gulp.