The quartet all failed to even make it on to the substitutes' bench for Wednesday's latest fixture against Preston North End, with competition for places fierce at Hillsborough.
Wednesday have one of the largest squads in the Championship, and Carvalhal admits that his selection decisions are becoming very difficult to make.
“I can only pick 18 in the squad so it breaks my heart when I couldn’t put in Semedo, Sougou, Bus and Palmer," he said.
“They are working a lot and deserve to go into the 18.
“They are fantastic professionals and we have a fantastic group and believe they can help the team in the future.”
Carvalhal has tinkered with his Wednesday team this season, with numerous players having to bide their time as they look for a run of games in the first-team.
The Owls have quality in every area, and the class that they have assembled is starting to shine through, now that the summer additions have settled in.
Wednesday have won their last four matches in all competitions, and they are rapidly climbing up the Championship table.
At the moment Carvalhal's side are just three points adrift of the playoff spots, with their next fixture coming against Hull City after the international break.