How will the Yankees fill out their postseason rotation?

The Yankees clinched the American League East and a first-round bye on Wednesday night, ensuring that they will have enough days off to align their postseason rotation however they'd like. 

What they won't be able to do, according to manager Aaron Boone, is put Frankie Montas into it. Montas is on the injured list with right shoulder inflammation, which is an apparent recurrence of an issue he had just before the Athletics traded him to New York in the summer. 

While Montas isn't expected to be out long-term, Boone told reporters over the weekend that "it's probably getting to a point where it's going to be tough as like a starting, built-up option." Montas resumed throwing on Saturday, a week-and-a-half before the Yankees' postseason opener.

The Yankees were hoping to have Montas be a frontline starter in the postseason, especially after they traded Jordan Montgomery at the deadline. Instead, they find themselves thinner on depth.

Gerrit Cole remains the ace of the staff and is in line to get the ball in Game 1 of the ALDS. While he's had a few blowups this season, there's no question Game 1 belongs to him. 

Nestor Cortes Jr. is set to start Game 2, which will come with even more rest thanks to a unique schedule this year. Cortes has had an excellent year and has returned to early-season form since returning from a brief IL stint. 

Game 3 was where Montgomery could've slotted in if the Yankees hadn't made the deal with St. Louis. With no Montgomery and no Montas, Luis Severino and Jameson Taillon seem to have the final two spots locked up. Taillon might have a leg up on the Game 3 role after his impressive start in Toronto on Wednesday, but Severino has performed in high-pressure situations in the past. 

Severino's stint on the 60-day IL might prevent him from giving the Yankees a ton of length — he threw only 76 pitches in Tuesday's start — so his start could be an opportunity for Montas to be a multi-inning reliever if healthy. 

Teams typically don't need five starters in the postseason, and the Yankees are fortunate to have Cole if a starter is needed to pitch on short rest. It's always good to have depth, however, and Domingo German is an option if one of the four starters goes down with an injury. 

The Yankees will face strong pitching in the ALDS regardless of whether their opponent is the Guardians, Mariners or Rays. It's critical that this unit performs like it has all season, and that starts with Cole after his rough postseason start a year ago.