Van Dijk was heavily linked with a transfer to Anfield, and after it failed to materialise he submitted a transfer request that was turned down.
But Yoshida told reporters that the Netherlands international was happy again after beginning the season out of the first-team picture with a foot injury.
Yoshida, whose team take on Brighton in the Premier League on Sunday, said: “He is good. He is enjoying every day. I think he smiles a lot.
“It is very comfortable with him — he never brings any negativity. That’s his future, his decision. But in this moment he is really comfortable, I think.”
“Maybe in the future something will happen, but at this moment he gives everything to the club. That is very good.”
Japan international Yoshida added that he felt Van Dijk had made good progress since returning to action for Southampton.
He said: “Recently he has done very well and I can see he is very comfortable, with more confidence.
“Game by game, we feel much better.”
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