The Netherlands international was an unused substitute as Chelsea beat Southampton 1-0 at Stamford Bridge in the Premier League on Saturday, thanks to Marcos Alonso's free-kick at the end of the first half.
Van Dijk was dropped after Southampton's 4-1 home defeat at the hands of Leicester City last time out and Mauricio Pellegrino's side did not appear to miss the centre-back, who handed in a transfer request in the last window.
Liverpool were forced to apologise after being accused of making an illegal approach for Van Dijk, while Chelsea are among the other clubs to have been linked with the 26-year-old.
But Conte, whose team have won eight of their last 10 Premier League matches, would not say if Chelsea could make a move for Van Dijk.
"As you know very well, I don't like to talk about other players of the other team," Conte told reporters at a news conference.
"It's not good. It's a lack of respect for my players, especially, and then for the other team, in this case for Van Dijk.
"He's a really good player. He had a bad injury, but I think he recovered very well. I wish him the best."
Southampton manager Pellegrino welcomed Van Dijk back to first-team action after he trained separately from the group for a period after putting in his transfer request.
The Argentine - who accused unnamed players of lacking "commitment" after the 4-1 midweek loss to Leicester - was unable to confirm whether Van Dijk will remain at the club through the January transfer window.
"Obviously Virgil is an important player," Pellegrino said after the game. "It always depends how they are, the energy they've got in every training session. A lot of things make an important player.
"I will repeat that I can't control the market. I'm not the owner of the player. I can have my opinion and this I have given to the technical director, to the chairman. After the board can decide altogether which is the best for the team.
"I can't control this. I will recommend to try to keep our best player here in the club. The club was clear in the beginning and I have the same opinion."