Manchester United keeper David De Gea was unhappy with boss Jose Mourinho over his remarks following the Red Devils' 0-0 draw with West Brom earlier this month.
The Spaniard dropped a Darren Fletcher effort which bounced off his crossbar to deny the Baggies all three points.
Mourinho downplayed the mistake during his post-match analysis but M.E.N. Sport understands De Gea took exception with the wording.
"David De Gea was sleeping and he did the funny thing at the end," Mourinho said. "I was laughing with that."
De Gea then conceded carelessly to Everton's Phil Jagielka three days later as United eked out another draw through Zlatan Ibrahimovic's stoppage-time penalty.
Mourinho said De Gea sat out United's weekend match at Sunderland with a hip injury and expects him to return to the United line-up against Chelsea at Old Trafford on Sunday.
Sergio Romero is expected to continue in goal at Anderlecht in the Europa League.
"It's good for Sergio Romero to play before Brussels," Mourinho said. "De Gea will probably be fit for Chelsea, yes. If he's in good condition."
Romero has started the last five United Europa League matches and made an impressive save to deny Victor Anichebe with the scoreline at 1-0 at Sunderland.
Mourinho ruled Wayne Rooney, Juan Mata, Ashley Young, Chris Smalling and Phil Jones out of the Anderlecht first leg and added Antonio Valencia was the only injured player likely to return.
He did not mention De Gea among United's injured or returning players.
Real Madrid's interest in De Gea has intensified recently after they failed to sign him from United on transfer deadline day in 2015.
Mourinho killed Real's lingering interest in De Gea shortly after he was announced as manager and and privately stressed it would be illogical to sell one of United's best players.
M.E.N. Sport revealed in the days between Louis van Gaal’s sacking and Mourinho's appointment De Gea was happy to stay at United under the Portuguese. De Gea and Mourinho are both represented by the agent Jorge Mendes.
The Spain international was placated in the summer by the arrival of goalkeeping coach Emilio Alvarez, who oversaw the Spaniard's development as a teenager at Atletico Madrid.
De Gea is contracted to United until 2019 and the club has the option of an additional year.
It is understood United would demand at least double the £32.6million Juventus paid Parma for Gianluigi Buffon - which remains the world record fee for a goalkeeper - in 2001.
Real are also keen on Chelsea stopper Thibaut Courtois.