- Higher winds expected on the Boston course
- Leaders Chappell and Casey tipped to hold their form
- Spieth and McIlroy a little off the pace
The championship is the second of the four tournaments that make up the FedEx Cup and with a top prize of more than $1 million, the world's best should be able to showcase their game.
But experts sounded a note of caution on the PGA website, warning that the breeze might dry out the greens and with higher winds expected later it could shake up the leader board when the front runners are on the TPC Boston course.
Former PGA Tour winner Dennis Paulson is tipping leading golfers, American Kevin Chappell and Englishman Paul Casey, to keep their form.
With the third round drawing to a close, Casey pulled away with a one-shot lead at 13 under with a group of four Americans, including Chappell, chasing hard.
Another pack made up of Ryan Moore, Jimmy Walker and South African Louis Oosthuizen are close behind. And two of the big names -- Rory McIlroy and Justin Rose -- are still in the hunt at nine under.
Oosthuizen carded a third round score of 64 with three birdies on the back nine to stay at nine under and he was joined by Rory McIlroy who finished the day with a round of 66.
American Patrick Reed, who won the first of the FedEx tournaments at The Barclays
last weekend, is in the top 20 and a handful of shots off the lead.
However, golfing giant Jordan Spieth has slipped away to three under.
Jason Day continued his push with a third round score of 68 despite being informed Friday that his wife and children had been involved in a car crash
. They were taken to hospital as a precautionary measure, the golfer said in a statement.
The Deutsche Bank Championship is the second of the four tournaments that make up the FedEx Cup. After this weekend's play, the field will be cut down from the leading 100 players in the Fed-Ex Cup rankings to the top 70 for next weekend's BMW Championship at Crooked Stick Golf Club in Carmel, Indiana.
The top 30 players will then compete for the overall Fed-Ex Cup title at the Tour Championship held at the East Lake Golf Club in Atlanta, Georgia, between September 22 and 25.