The Nigerian striker has not played for the Baggies since his madcap deadline-day dash to QPR in a bid to force through a move.
Clarke said: "We try to treat all our players like adults. You can't sit them down and say you can't do that.
"It's difficult to stop people from tweeting - 99 per cent of them use it very well.
"It's every now and again you get one line that causes a stir."