Sako, 30, joined the Baggies in October on a contract until the end of 2018-19 after leaving Palace in the summer.

However, he started only three games for the Championship side and they have agreed to release him from his deal.

"I hope his return will be a major boost as we enter the business end of the season," said Crystal Palace manager Roy Hodgson.

"He's a player with a huge amount of talent and, as he showed when he was fully fit last year, he is able to provide a boost to our attacking options."

Mali international Sako scored eight goals in 50 appearances during his first spell at Selhurst Park between 2015 and 2018.

Before that, he netted 38 times in three seasons with Wolves.

Baggies head coach Darren Moore intends to use Sako's reported £30,000-a-week wages to invest in other attacking options before the transfer window closes on Thursday, reports BBC WM.

"Bakary has not played as much football for us as he would have wanted," said Moore.

"He was eager to take this opportunity in the Premier League. We decided it was in everyone's best interests for him to move on."