Too many variables and you must remember the philosophy of TINSTAAPP. Pitchers will fade out as they have high injury and ineffectiveness rates and some will invariably move to the pen. We have a ridiculous amount of pitching talent, though. If you want to play that game, I think it's best just to see the depth chart as is
Severino
Montgomery
They have locked up long term roles. I know JMont just went down to AAA, but it wasn't due to performance. I think they're keeping him stretched out as insurance until Sept 1 and he comes back up as a lefty reliever when rosters expand. NYY knew after getting Gray that he wasn't going to be on the PO pitching staff, and they went with veteran consistency in Garcia (we shall see).
The high level wave
Adams
Sheffield
Acevedo
Adams is the most complete pitcher. All of the above sit mid to high 90s. All have at least one good secondary pitch. Adams is a 4 pitch pitcher with the best command of the bunch. Sheffield is the youngest and he's the lefty here. Acevedo has the most power. All 3 have top half of the rotation ceilings with Acevedo's ceiling is probably the highest yet toughest to reach due to his size and power
The fringes of the high level
Mitchell
German
Cessa
These guys all have been on the shuttle with varying degrees of success and frustration. All have power, with Mitchell able to run it up into the high 90s. All have inconsistent secondary stuff. If either of them click, they do have the kinds of power arms that could lock down a slot, but they're being passed by the guys above
A Ball
Tate
Perez
Abreu
There's more talent in A ball, but these are the giants down there. The rest need to sort themselves out as there are plenty of guys with big arms who look pen destined. Tate was drafted 4th overall in 2015 but his mechanics were all screwed up with Texas. We got him for Beltran and initially converted him to pen work. He worked on his mechanics all offseason, but had an injury that limited him out of the blocks. Since coming into the rotation in Tampa, he has been lights out. They haven't moved him aggressively because I think the Yankees just want him to have a successful year, but he's going to be fast tracked next year. He has true ace level stuff and he might end up being the best pitcher in our system if he hits his ceiling. Perez is huge with a huge fastball, good command and already a plus breaking ball. NY goes slow with the giants, so he will likely go one level at a time for this and next year. Abreu has the best velocity in the system, routinely hitting 101-102. He's also currently injured and has missed most of the season. My assumption is it is arm related and I hope if it's elbow they just fix it before we run into another Kaprielian saga
The Rest
Guzman
Schmidt
Sauer
This is the pile the Yankees will draw from. We just drafted 9 out of our top 10 picks as pitchers, so guys can emerge from this at any time. Guzman we got with Abreu for McCann. He throws 100 with developing secondary stuff. He's in the NYP dominating and looking like he might jump to Tampa out the gate next year. Schmidt was a top 10 pick before needing TJS. He's noted to have a hard sinker running mid 90s with the secondary pitches and stuff to be dominant. We shall see how he does when he is healthy towards the end of next year. Sauer is the HSer we drafted who tops out at 98 with a wipeout slider. We will likely try him on the mound as a starter and see if he can work on a change.