Furious boss Jos Luhukay criticised Owls midfielder Josh Onomah's performance after their 2-1 away defeat to Swansea City.
In the absence of Barry Bannan, who is unavailable for selection for two matches after accruing 10 yellow cards, Onomah was handed his first start in just over a month.
But the Tottenham Hotspur's loanee, one of just three signings made by Luhukay since he took over the Wednesday reigns last January, was taken off at half-time and replaced by Marco Matias.
Luhukay told The Star: "He was not good enough. He brought nothing on the ball.
"He lost three, four, five balls right at the beginning (of the game). That is the reason why he came off and we changed it.
"Honestly, he had no influence on the game."
Onomah has struggled to make an impact since moving to Hillsborough at the end of August. The England Under-21 international, who spent last season on loan at Aston Villa, has made just seven starts and two substitute appearances.
"That was his chance but you must take it when you have the chance," added Luhukay.
Wednesdayites called for Luhukay's dismissal in the wake of their seventh defeat in the last 10 matches.
It looked as if the Owls were going to secure a first away win for more than two months when Matias punished Joe Rodon for a defensive error after 63 minutes.
But Bersant Celina stepped up off the bench and played an instrumental part in Swansea's remarkable comeback as the attacking midfielder scored one goal and created another to heap more pressure on Luhukay.
Defeat leaves Wednesday in 18th position, just five points above the relegation zone.
Luhukay, who walked out on a post-match radio interview after he was questioned about his future, said: "It is unbelievable that we gave the one goal lead so easily away. I'm completely frustrated and it was not necessary. We had the control.
"I am so angry because the players are showing no proof of what we are doing. It is not the first time we have gone one or two nil in front and in three or four minutes we give the game completely away. It is painful."