Leeds slipped to a 2-0 defeat away at Brighton on Saturday with the Whites turning in an abject performance on the south coast in the Premier League clash.
Marcelo Bielsa’s men had just two shots on target throughout the entire 90 minutes and Klich completed the game, with goals from Pascal Gross and Danny Welbeck the difference for the hosts.
Whelan, who feels the Poland international has declined through the season, admits he did not even know Klich was on the pitch in the first half as he was so ineffective.
The former Leeds man believes it is essential the club look to sign another midfielder in the rapidly approaching transfer window.
“You look at his energy levels, he’s losing his battle today to [Yves] Bissouma all over the place”, Whelan said post match on BBC Radio Leeds.
“He doesn’t look like himself, didn’t not even really get that many touches in the first half to be honest. Did not realise he was on the field at times.
“When you talk about do we need more midfield players, do we need to go into the market in the summer, absolutely.”
Leeds tried to land a new midfielder last summer, but saw a late move for Michael Cuisance collapse at the last minute due to an issue with the player’s medical.