He was selected as a specialist batsman for that match, with England dropping Zak Crawley from their top order to make room for an extra bowler.
"We still need to know a bit more about where Ben is at," Root said at his pre-match press conference.
"It's a bit like telling him after nine overs on the bounce not to bowl and trying to take the ball out of his hand -- it's difficult," he admitted.
Alternatively, they may decide to drop Somerset spinner Dom Bess and rely on Root's occasional off-breaks for variation in a seam-dominated attack.
England have lost the first Test in each of their past five series.
"I think it is really important we don't take that for granted," he said. "We are very aware Pakistan are a talented team and very 'up' for this series."