How the Dodgers will look to fill out a once-crowded starting rotation

PHOENIX — While Yoshinobu Yamamoto takes the mound for Japan in the World Baseball Classic, the Dodgers are confronting a familiar spring-training riddle: how to piece together the back end of a rotation that has already lost two projected arms.

Manager Dave Roberts confirmed that left-hander Blake Snell is expected to open the season on the injured list with a shoulder issue, and right-hander Gavin Stone has been shut down from throwing as he recovers from major shoulder surgery. Those setbacks thin a group that, on paper, still features three certainties: Yamamoto, offseason import Shohei Ohtani and hard-throwing Tyler Glasnow.

The competition for the remaining spots has turned into a high-stakes audition in the Cactus League. Hard-throwing Roki Sasaki, who flourished as a reliever last October, is attempting to stretch back into a starting role but has been tagged for seven runs in two spring outings while surrendering frequent hard contact. Roberts said the club will schedule a simulated game for Sasaki on the Camelback Ranch backfields in addition to his next exhibition start, an effort to accelerate his buildup without sacrificing results.

Sasaki attributed his recent four-run, zero-out first inning to mechanical drift, but Roberts saw a simpler culprit: “He just wasn’t making pitches early and we have to get him to four innings. … We gotta build up, all the while being good, too.”

Emmet Sheehan, 26, returned from Tommy John surgery last July and posted a 2.82 ERA in a dozen starts. After missing early camp time with an illness, he worked four outs Wednesday against Team Mexico, allowing one run on three hits and two walks. Sheehan said his delivery felt sound and plans to sharpen fastball and slider execution in upcoming bullpen sessions.

Right-hander River Ryan, also on the mend from Tommy John, continued his comeback with two scoreless frames Wednesday and has yet to allow a run in two Cactus League appearances. Left-hander Justin Wrobleski, a postseason bullpen stalwart who spot-started during the regular season, has tossed three scoreless innings this spring, including one start.

With Snell and Stone sidelined, the Dodgers will lean on that trio—Sasaki, Sheehan and Ryan—along with Wrobleski to bridge the gap until reinforcements arrive. How quickly they can build endurance and refine command will determine whether Los Angeles enters the regular season with a full five-man rotation or must again dip into its enviable depth.

Yamamoto’s durability sets the standard: he was the only Dodgers starter to make every scheduled turn last year, finishing with 30 regular-season starts and five more in the playoffs. If the candidates behind him follow suit, the club’s once-crowded rotation could regain its depth sooner than the injured list suggests.