Cardiff City manager Neil Warnock accused Liverpool of “a lack of class” after Reds defender Nathaniel Clyne completed a move to Bournemouth.
Clyne, 27, made his professional debut in 2008 under then Crystal Palace boss Warnock, who expected him to join Cardiff this month.
However, on Friday the England international joined Bournemouth on loan until the end of the season.
“It’s a disgrace,” Warnock told BBC Radio Wales.
“I was disappointed with Nathaniel Clyne, having known the player and giving him his debut [during their time at Crystal Palace].
“I’m not just disappointed with the boy himself, but with Liverpool as well for not ringing me, not telling me.
“To see it on television when I’ve done everything right and they have promised that he is my player this week, it’s a disgrace and a lack of class.”
Clyne started only one Premier League game for Liverpool this season, with 20-year-old Trent Alexander-Arnold selected ahead of him.
Liverpool are four points clear at the top of the table, while Bournemouth are 12th – nine points clear of 17th-placed Cardiff.
Clyne made his Bournemouth debut in the 3-1 home defeat by Brighton in the third round of the FA Cup on Saturday.