Clarke is expected to select an experienced trio to join a rookie-heavy line-up of nine automatic qualifiers, with stalwarts Lee Westwood and Martin Kaymer widely tipped for inclusion.
That would leave one more spot to Clarke’s discretion and Donald’s candidacy received an apparent boost on Monday from a flurry of betting activity supporting his inclusion despite a long barren spell.
Donald has not won on either the European Tour or the PGA Tour since winning the BMW PGA Championship at Wentworth in 2012, although he offered a timely reminder of his class by finishing second at the Wyndham Championship earlier this month.
The 38-year-old former world No1 has been part of four European Ryder Cup victories and has been notably potent in the foursomes format, winning six and drawing two of eight matches.
He is only 21st in the Ryder Cup world points list, however. By that measure Scotland’s Russell Knox, who has two PGA Tour wins this season, and in-form Belgian Thomas Pieters, who underlined his credentials by winning in Denmark on Sunday, are the leading contenders.
Westwood, a friend of Clarke’s, is in line for a 10th consecutive Ryder Cup appearance. Kaymer holed the putt that ensured Europe retained the trophy in 2012 and has been part of the last three winning teams.
Patrick Reed, meanwhile, secured his place on the United States team by winning The Barclays, the first leg of the FedEx Cup Playoffs, on Sunday.