The Nigerian international made seven appearances for the Whites and also had a brief spell with Watford earlier in the campaign.
"Sam's been outstanding," Grayson told the club's official website. "He's rarely trained with us due to his need to rest between games but he has done well in the games he's played.
"He's done well, he will discuss his future in a meeting with Reading and once any decision is made we'll see what's what.
"I thank him for his efforts as I do with Carl Dickinson, Liam Dickinson and Lee Trundle and everyone who came on loan."
And Grayson has hinted at bringing players in on loan again next season, he added: "I don't mind using the loan market. It freshens up the squad and keeps everyone on their toes, whether it's month-to-month or six-month or season-long loans."