The Potters will host the Black Cats at the Stadium of Light in the Premier League and will have to confront the Scotland international, who has scored five of his side's six goals this season.
Pulis, who was interested in signing the 25-year-old in the summer, believes that Fletcher will have to be paid special attention in order for his team to bag maximum points.
"If you look at the records so far, with the goals he's scored, obviously he's going to be a danger," he said. "We might have tried [to sign Fletcher] but we've tried with a lot of players.
"But they've got good midfield players. If you look at Adam Johnson, [Sebastian] Larsson's very good off set plays. [James] McClean is good on the other side. [Stephane] Sessegnon can win games.
"They've got experience at the back so they're a decent side.
"They've got some very good players and he (manager Martin O'Neill) has got the basis of a very decent squad there.
"They're a bit like us. They need a couple of results and a couple of breaks just to get themselves moving. I see them as being, they are and will be, a very competitive Premier League side.
"We've enjoyed the season so far. It's been a tough start. We've played five of the first eight games away and two of our home games have been against Man City and Arsenal so it's been a very difficult start for us."