Jason Day now has renewed concerns for his immediate future after it’s been revealed he re-injured his troublesome left thumb during last week’s Masters.

The 26-year old Australian had planned to enter this week’s RBC Heritage Classic at Hilton Head in South Carolina.

However the reigning WGC –World Cup ‘Individual’ champion and winner of February’s WGC – Accenture Match-Play Championship withdrew before teeing-up in the $US 5.8m event.

PGA Tour officials were advised of his withdrawal earlier in the week and with word from his management company Day has had his thumb placed in a cast for precautionary measures.

However it has come to notice Day re-injured his left thumb after hitting a tree root during last Saturday’s third round of the Masters.

In fact, it was a tree root growing out from ‘Mickelson’s Tree’, the tree down the right side of the par five, 13^th hole at Augusta National from where Phil Mickelson landed a 207-yard 6-iron from between trees to three feet for an eventual birdie and help set-up a second Masters success in 2010.

“Jason jarred his thumb hitting a buried tree root at Phil’s tree on Saturday and that’s why he’s not playing this week,” said Col Swatton, his long-time coach and caddy, who has stayed on at Hilton Head.

“I know he’s disappointed but there’s not much Jason can do about it,” said Swatton.

“He’s again getting further treatment on the thumb and it’s been placed in a cast but really the only cure is rest”.

Day’s appearance at the Masters was his first tournament in six weeks since first injuring the thumb and prior to the injury he was headed into the year’s first Major as a joint favourite to win the green jacket.

He arrived at Augusta playing down any concern including being observed a few times during Friday’s round fiddling with the tape supporting his thumb that had come unstuck.

“There’s no issues with it and it’s just the tape’s coming off,” Day said after last week’s second round.  That’s why sometimes you see me rubbing it, just trying to get the tape back on.  But it’s fine.”

But when Day ended his round on Sunday with a round of 72 to eventually finish in a share of 20^th place the Ohio-based Australian again remarked the thumb was ‘fine’.

The re-injuring of Day’s thumb now has him in doubt for next month’s $US 10m Players Championship and June’s US Open at Pinehurst No.2.