FIFA's developers made a complete overhaul of the game engine for the 2006 installment of the game, claiming a dramatic increase in the control of play, having rewritten more than half the game's code. In addition to a renovation of the engine, which discards the "off the ball" system, the developers boasted a significantly more involved Career mode and the introduction of "team chemistry" which determines how well team members play together. This installment breaks with the long tradition of commentary from Match of the Day's John Motson and (more recently) Ally McCoist, who are replaced by ITV's Clive Tyldesley and Sky Sports pundit Andy Gray, who had already worked in the series as guest commentator. The players featured on the front of the game are Wayne Rooney and Ronaldinho.