League just rolled over. I have a couple studs who just started last year of contract. Both say they're gonna test free agency. Is there anything that can be done during the course of this season where they change their minds, or is it inevitable they go to FA?

Nope. Just double-check once budgets are set to make sure they still say the same thing. Otherwise, you are outta luck. Get ready to bid for them next season.

It's not a hard stance no. I once had a FA to be who was going to test FA. During the season player got hurt and lost some rating points and I was able to resign him. He went from an overall 84 to 79, for context. Other than that I don't think so.

Just gonna leave this here in case anyone doesn't know it can happen.
Last season I traded for a player on an expiring contract. Was fairly certain he was going to be a Type A, but also interested in signing him long term.
Since he has 95 Patience, I figured to wait till this season after setting my budget.
At rollover, he was willing to re-sign.
Right after budgets set, guess what, he was the top Type A on the market and he flipped to "I'm filing for free agency no matter what."
I offered his demand with a small increase and no one else bit. I just got him back. But turned out, I should have signed him last season.