@rpapo
In my opinion this is the sort of situation where you are pretty much
forced to give an interpretation of the usual Japanese vagueness, or otherwise the line won't work. You have to decide what the character is trying to say (knowing the whole plot may help) and add that meaning to the end result. Of course, it is possible to guess the character's/author's intent wrong and end up with a mistranslation, but that's a risk one has to take; English simply doesn't tolerate the same level of vagueness.
In this specific situation, it sounds like the teacher is referring back to something she said previously - the huge question is what. The best candidate to me (without reading the raws or knowing anything about what's to come) would be her last few lines on the previous page, where she says that Matsubara is usually trying his best at school because he wants to leave, but now something must have happened that shook that resolve (am I getting this right?), considering how his grades have dropped.
So, if that really is the part she's referring to, this line could have been something like "I guess what I'm trying to say is, could it be that your priorities changed?"
It's a good sign that this version would fit the MC's thoughts right afterwards as well... or at least I think it would. Ugh, now that I'm rereading those three lines, they are also incredibly vague... XD