Coming into the season, one of the biggest question marks surrounding the Yankees' roster was their rotation depth. Their starting five of Luis Severino, Masahiro Tanaka, CC Sabathia, Sonny Gray, and Jordan Montgomery is certainly well above average, and their combined talent has led the Yankees' staff to be projected as one of the better squads in MLB. After that, though, the Yankees' starting pitching depth chart consists of names like Luis Cessa, Domingo German, and Domingo Acevedo. None of them are projected to record ERAs or FIPs below 4.65. In the event that, heavens forbid, one of their starting five goes down, the Yankees' run prevention department will take a huge hit.
Surely the Yankees know this, and yet they did not make a move for a free agent SP to shore up the back of the rotation. Granted, it's hard to argue that the available options (Alex Cobb, Lance Lynn) were clear upgrades over any member of the Yankees' current rotation. However, it's easy to argue that Cobb, Lynn, or Montgomery (who probably would have been the odd man out had the Yankees signed anybody) would have been a clear upgrade over Luis Cessa. So why did the Yankees stand pat?
After some thinking, I'm willing to give the Yankees the benefit of the doubt due to three main reasons: one, they have the firepower to win slugfests; two, they have the bullpen to salvage bad starts from Cessa or other depth options; and three, they can reinforce the rotation mid-season, either by relying on MLB-ready prospects or trading for a starter from their prospect depth.
The first reason is pretty obvious. I was originally going to post a gif of Stanton's two monster dongs from Opening Day and call it a paragraph, but I want to keep this gig so here are some numbers. Say something horribly goes wrong and Cessa gets 15 starts or so. The major projection systems all peg Cessa for an ERA at or a little over 5. For simplicity's sake, let us assume that the average Cessa start will look something like 4 IP and 2 to 3 earned runs (which was the case last year). Meanwhile, per FanGraphs, the Yankees are projected to score 4.79 runs per game, the highest figure in the MLB. This means the Yankees' lineup, barring a team-wide extended slump, should generally be expected to score enough runs to salvage more than half of Cessa's starts.
Now, the paragraph above assumes that the Yankees' bullpen will be able to clean up Cessa starts and give the offense a chance to do its thing. This brings me to reason number two: the Yankees' bullpen is a monstrosity. In Chad Green, the Yankees have a shutdown reliever who can handle multiple innings at a time, enabling Aaron Boone to pull Cessa (or any starter, for that matter) early before too much damage is done. In Tommy Kahnle, David Robertson, Dellin Betances, and Aroldis Chapman, Aaron Boone has an embarrassment of riches to choose from to handle the later innings. Further development from Jonathan Holder (who I really like) or Ben Heller would provide Boone with even more viable options, alleviating concerns about overworking elite relievers. It's safe to say that the Yankees' bullpen should keep the Yankees in any game.
Thirdly, Cessa/German/Acevedo aren't all of the Yankees' SP6 options. Justus Sheffield has been lauded as a low-risk, potential mid-rotation starter, and Eric Longenhagen thinks that he should reach the majors at some point this season. Ditto for Chance Adams, who Longenhagen is less enthusiastic about, but still thinks that he could be a credible back-end starter. And should the Yankees desire so, they should be able to parlay some of their considerable prospect depth to acquire a starter from a non-contending team - maybe Michael Fulmer or Chris Archer - at the trade deadline. The Yankees' front office can still make sure that Luis Cessa doesn't start 20 games, and they should.
With these three factors in mind, the Yankees' decision to roll into Opening Day with Luis Cessa as their 6th starter becomes much more defensible. Granted, it's possible that injuries pile up, causing the Yankees' current lack of rotation depth to be further exposed. However, literally no team in baseball is well-equipped to survive more than two starting pitchers going down - well, except the Astros, maybe. The Yankees should be fine even if one of their top five starters goes down, and I guess we should take comfort in that. Just hope I didn't jinx anybody, and get those voodoo dolls ready just in case.