It's been a traumatic season for Barton since he arrived on Tyneside in a £5.8m move from Manchester City last June, but Keegan believes the midfielder can still make an impact at Newcastle.
Keegan: "I just thought Joey kept going against West Ham last Saturday, when some around him were finding it tough, he just kept going.
"He has got a terrific engine on him. I always think Joey gets more into a game as it progresses.
"You know at 70 or 80 minutes, he's still going to be making the same runs.
"He's still got the same determination and fitness levels. Like Oba, he gives us something that nobody else does.
"And if you've got a lot of players giving you something that nobody else does, and put it together and work hard, sometimes you can fashion a great team out of it."