What's wrong with using that game to see how he fares against a PL opposition? Though he may have played well in the Champions League before but those games were against Zilina and a dead rubber against Marseille. Furthermore, he hardly got to play consistently in the Premier League last season with Swansea but now he is playing week in week out for Boro in the Championship and coming up against different level of opposition suddenly will be a good test for him, assuming if he plays. Adding to that, this is local derby game, where the atmosphere and intensity of the game will be high thus making it interesting to see how he copes with it.