Maresca was asked about captain Reece James after a 2-1 loss to Liverpool last weekend.
He said that while James was performing since his return from injury, he needed to be more vocal on the field.
"I spoke with him and I expect from him more in terms of leadership inside the changing room," he said to reporters.
"He's on the way, he's doing well, he's progressing but I expect more.
"Most of the time, a player thinks that 'because I am captain I expect that you (the manager) give me more'. No, for me because you are the captain you have to give more.
“You have to give more than the rest. I expect it from Reece and his team-mates expect it from him to give always more in terms of leadership."
Keane told Sky Sports: "He's obviously been injured and he sees him on the training ground, he got back involved last week. I'd have no problem with a manager saying that he wants more from him. What's the problem with saying that?
"It's nice now and again to upset your own players and maybe he's just trying to gee him up a bit. He knows his back from injury and he wants him to stay fit and healthy. We know what a brilliant player he is, but he works with him day in and day out and just wants a bit more from him.
"He can't be someone he's not but you can show leadership in different ways. There's nothing wrong with the manager throwing a hand grenade into his own dressing room just to upset a few and keep people on their toes. That's part of it."