When asked how he feels about the OC change, he basically turned it back on the reporter and asked “what does it matter?” And that’s exactly the point, it doesn’t matter. It’s a done deal. Shut up and play, which is what Diggs meant by emphasizing he’s a professional.
It seems clear to me Diggs isn’t happy about a lot of things internally, but doesn’t want to fan the flames by speaking out about it. It’s what he doesn’t say that is speaking most loudly here.