No doubt players adjust or try to adjust many times over their career. Sometimes it works, while other times it doesn't work. Players are often asked or "suggested" to make adjustments or changes to their approach, stance, swing or other areas of their batting.
We've seen Duran change his approach, stance and other aspects of batting several times at the MLB level, and word was he adjusted many times in the minors, too. His muscle mass also underwent a significant change. We can assume one or more adjustments and or the increased strength have worked.
There are examples where hitting coaches were blamed for players' declines in production.
I certainly think this scenario could happen:
1. The team asks Rafaela to change his approach and attempt to be more selective, or he decides to try it himself.
2. He makes some sort of adjustment to swing less at balls outside the K zone of maybe just swing less, overall.
3. The change in approach messes up his swing or confidence, or he stops swinging at balls he should have swung at and sees his production drop.
4. Then, he wonders how long he should give the adjustment a chance and if he returns to his old way, can he get back to the level he was before trying to "improve." Now, he's got issues in his head to deal with, when before he was successful, because he was more or less carefree about is approach and that worked for him, at least well enough to be above the league OPS.