Sell him and watch him fall apart at another club.
He needs a team built around him to be half what he is, he wouldn't get that anywhere else in the Premier league and I doubt he will want to go down a league.
Plus the top defenders will just close him down and stop him playing how he likes too making him all pissy so he plays worse.
Probably sell him in the summer. At least do something for half the season and then leave when he's actually contributed. Warnock will want him in the first-team eleven even if it's for a little while and see if the club can stave off relegation (even though it won't be wholly down to Taarabt's performances)