Preston have recalled the 20-year-old midfielder from his loan spell with Colchester United due to Stuart Beavon's three-match suspension.
Grayson has said that he does not want Monakana to waste his talents.
"We brought Jeffrey back because Stuart Beavon is out for three matches now," Grayson told Sky Sports News.
"We haven't got the biggest squad in terms of the numbers we've let out on loan, but we've done that for a reason. Jeffrey only had two weeks left and he couldn't play against us in one of the games so we felt we might as well utilise the situation and we can have another body around.
"It's come to the stage where Jeffrey really needs to grasp everything that we want him to do. I don't need a player in my squad that's only going to be effective for 10, 15 minutes here and there. I'd say he's maybe in the last-chance saloon with us. His contract runs out in the summer."
Monakana made nine appearances during his stint at Colchester.