
World number one Rory McIlroy has offered another clue which suggests he plans to return from injury to defend his USPGA Championship title next week.
McIlroy suffered a "total rupture" of ligaments in his left ankle during a game of football with friends on July 4, ruling him out of the Scottish Open and the defence of his Open and WGC-Bridgestone Invitational titles.
The 26-year-old has yet to say whether he will be able to compete at Whistling Straits next week, but on Friday posted a picture on social media which appeared to show the inside of a private plane along with various emojis depicting a US flag, a thumbs-up symbol and a golf flag.
The on-board video screen suggests McIlroy was departing from Faro in Portugal, where the four-time major winner is understood to have been practising and the location for Thursday's video of him hitting a driver on the range.
On Wednesday McIlroy posted a video on his Instagram account in which he was seen balancing on his left leg and twisting and throwing a gym ball to mimic the actions of the golf swing.
Alongside the short video clip, McIlroy wrote: "Working hard every day to come back stronger #dontmindthegrind."
He has also shared photographs of his ankle from four and three weeks ago, saying: "I've come a long way since."
McIlroy will be replaced as world number one by Masters and US Open champion Jordan Spieth if the 22-year-old American can win his first World Golf Championship title at Firestone Country Club this week.
It was at the same event that McIlroy overturned a three-shot deficit to Ryder Cup team-mate Sergio Garcia in the final round 12 months ago to move back to the top of the rankings.
McIlroy's last competitive round was a closing 66 in the US Open at Chambers Bay on June 21. The USPGA gets under way on August 13.