Stefano Pioli lamented Rafael Leao's "strange" lack of form after the Milan forward endured another underwhelming outing in Monday's 1-1 Serie A draw with Salernitana.
The Rossoneri failed to capitalise on slip-ups from top-four rivals Inter, Roma and Lazio as Olivier Giroud's first-half header was cancelled out by Boulaye Dia after the break.
In a wasteful display which saw Milan record 24 shots but draw just two saves from Salernitana's Guillermo Ochoa, Leao attempted a game-high five shots – none of which found the target.
Having reportedly attracted interest from a host of European giants including Manchester City, Chelsea and Real Madrid after helping Milan win the Scudetto last season, Leao has struggled in recent weeks.
The Portugal forward has gone 10 games without scoring since finding the net at Lecce in January, leading Pioli to bemoan his inability to replicate his promising performances in training.
"Being close to my players is my priority, when things are going well or badly," Pioli said when asked whether Leao would benefit from more criticism.
"Leao's strange situation is this – in training he does very well, he moves a lot and does everything very well, then in the game he does less. He has to find a middle ground."
Milan's frustrating performance came five days after they secured a Champions League quarter-final spot with a 1-0 aggregate win over Tottenham, and Pioli refused to use fatigue as an excuse.
"No, there was no tiredness, but a lack of quality and players in the area," he said. "We weren't as fast as we could be, or as careful.
"When I have the team review the goal that we conceded… it was too easy to score. We had to manage the game better. We tried, but we had to be brighter and more precise."
Milan were denied a penalty shortly after Salernitana's equaliser, with referee Federico La Penna reversing his decision to award a spot-kick for Domagoj Bradaric's challenge on Ismael Bennacer after being sent to the VAR monitor.
Asked about that incident, Pioli said: "I honestly didn't see it again after the match, so I can't judge it honestly. Otherwise, I would say what I think."