The Sheffield Wednesday teammates were said to have come to blows on Thursday.
The speculation had emerged on Twitter on Thursday, and Carvalhal responded by telling the Owls' official Facebook page that such situations are to be expected in teams that train aggressively and with high intensity.
Owls boss Carlos Carvalhal
"To answer your question in general, sometimes when we see that any player ups the limits or crosses the line, we have rules, we have discipline and, of course, we will take care of the situation," Wednesday's head coach said during Friday's press conference. "As you understand, I will not (make) any comments about (specific) situations.
"Between the players, they are discussing positions, they are working hard. If you are training with high intensity, if you want the team to recover the ball, work hard, put the feet (in) and try to win the balls aggressively, this happens sometimes. They upset one another, sometimes they cross the line.
"This, as I tell you, happened in the past, it happens in the present and will happen in the future - in my team, in all the teams in the world."
Both Winnall and Forestieri are competing for places in an already congested Wednesday attack which also comprises Jordan Rhodes, Steven Fletcher, Gary Hooper, Lucas Joao and Atdhe Nuhiu.
Forestieri has also featured prominently on the left of midfield since his transfer to Hillsborough two years ago, but recently informed Carvalhal he would rather play through the middle.
Sheffield Wednesday forward Fernando Forestieri
The Italian-Argentine partnered Rhodes in attack for Saturday's 1-0 defeat against Preston, but the pair were replaced by Fletcher and Hooper against Chesterfield on Tuesday - both of whom scored in a 4-1 win.
The latter duo are therefore fravourites to retain their places when QPR visit Wednesday this weekend, although Carvalhal revealed that Fletcher's fitness will need to be assessed ahead of the game.