Potts completed a seven-figure transfer to Preston last Thursday - after the Reds accepted a club record bid from North End.
While acknowledging the loss of a key player, Winkler says that the nature of the transfer window means that players always come and go - if the right offers are fielded.
Winkler, busy preparing alongside head coach Daniel Stendel for tomorrow's Yorkshire home derby with in-form Bradford City, said: "We do not think about that right now. But we were really disappointed that he left us. He was a good player and a very nice person.
"But that is how it is in the transfer window. Players go and come and we have to go on and look forward.
"For some reasons, sometimes it is necessary. As a player and a club, there is a transfer window. If you look to other clubs, their manager can go and can leave the club in the winter transfer window and that is how it is."
The Reds report no fresh injury concerns and pick from strength for tomorrow's derby with the Bantams.
Daniel Pinillos is back in training, Winkler confirmed.
He said: "I think we have some good headaches and we have a strong side and the lads who do not start at the beginning put pressure on them (starting players). And it is not easy to come into (make) the squad at the weekend."