On Monday, the Yankees made the decision their fans cared most about. Jordan Montgomery will be the team’s fifth starter.

What some people don’t realize, though, is that the Yankees still need to make another decision. We know that Montgomery will make his major league debut Wednesday night against Tampa Bay at Yankee Stadium. However, because Montgomery is not on the 40-man roster, the Yankees need to make a move to free up a spot for him. And that’s what we don’t know.

The Yankees have up until Montgomery takes the mound to add him to the roster. So what will the corresponding move be? Well, the Yankees optioned left-handed reliever Chasen Shreve to the RailRiders shortly after manager Joe Girardi announced the decision to go with Montgomery. Still, that won’t cut it, seeing as how Shreve also is a 40-man guy. In fact, when he arrives to Scranton — which I think will be Wednesday — the RailRiders will need to make a move because their 25-man roster is full.

Why do I bring this up? It’s simple. Whatever move the Yankees ultimately decide to make to add Montgomery will in all likelihood involve someone being designated for assignment. After all, they aren’t going to transfer shortstop Didi Gregorius or catcher Gary Sanchez to the 60-day disabled list since both are expected to back sometime next month. I also don’t think a trade is likely at this point in the season.

When it first struck me that the Yankees needed to free up a spot for Montgomery, my first reaction is that they would DFA right-handed pitcher Ronald Herrera. But as I thought about it more last night, I quickly realized that it wouldn’t make too much sense. Sure, Herrera is on the minor league disabled list right now and there probably isn’t any use for him in New York at the moment. But he’s still just 21 years old and coming off a solid 2016 season at Double-A Trenton. I don’t think the Yankees are willing to chance letting Herrera go without getting something in return.

So who are the likely candidates to be DFA’d? To me, there are four: Shreve, Johnny Barbato, Dietrich Enns and Rob Refsnyder.

I think Shreve is the least likely. Sure, he was just sent down but he seems to be destined for a “Scranton Shuttle” role. At some point, the Yankees are going to need bullpen help and Shreve still has value, despite his struggles last season.

What I expect to happen is this: the Yankees add Montgomery and DFA a player who is on the RailRiders, which will then result in the RailRiders activating Shreve to keep their roster at 25 guys.

Ultimately, I think it’s going to come down to Barbato and Enns. I think Refsnyder still has value to the Yankees and can contribute on the field in some way. He’s not a standout defender by any means, but he’s not as horrible as some make him out to be. He may not have a long-term future in New York, but the Yankees would probably rather get something in return for him.

In the end, I think it’s going to be Barbato who is DFA’d because I don’t see where he fits in with the Yankees’ plan at the moment. Barbato still is in the process of transitioning into a starter. He made his first start on Saturday and had a 75-pitch limit. It’s clear to me that the Yankees don’t have any plans to call him up in the near future. The Yankees already have too many other starters as priorities — Chad Green, Luis Cessa and Chance Adams immediately come to mind — should one of their current five struggles or go down with injury. And it just wouldn’t make sense to bring Barbato up and use him out of the bullpen after he’s spent all this time stretching out as a starter.

Surely, you can say the same thing about Enns but he’s already established himself as a viable starter and even proved last year that he can transition to the bullpen. I think when and if he gets an opportunity with the Yankees this season, it will be in the bullpen as a middle to long reliever. That’s something Barbato is capable of doing as well, but I don’t think the Yankees would do that as he continues his transition.

I’m guessing we’ll know more by this time tomorrow. Considering it’s the Yankees, I wouldn’t rule out any move no matter how bizarre it may seem.