The £3m summer signing from St Etienne has put in a string of impressive performances so far this season, culminating in him scoring the winner during his side's 1-0 victory over Sheffield Wednesday at the weekend.
"He's brilliant. He can go by the full-backs with ease at times and I personally wouldn't like to play against him," Foley told the Express & Star. "He's explosive and he's got a great shot on him.
"He's very powerful and it's good to have players like that at this level. He can open up gaps for other players."
Sako has scored two goals for his new club.