"He could have an adverse effect in the team room. People have always seemed to try to do too much when they have partnered him. It might be different if he's one of the vice-captains - you don't know."
Europe are seeking an unprecedented fourth straight victory in the biennial contest and Westwood, who will make a 10th consecutive appearance after being given a wild card by captain Darren Clarke, believes the pressure is firmly on the home team.
"They have got a strong side and probably are favourites, but they haven't won it for a while and they are playing in front of a home crowd," the 43-year-old added.
"There is a lot of pressure on them.
"That is going to keep building in the next week or so and by the time the Ryder Cup comes around it is going to be pretty intense for them, the week in Minnesota."