Australia are in trouble in the first test and their prospects for the second took a hit with news fast bowler Mitchell Starc is battling a potential recurrence of bone spurs in his ankle which could put him out of the Ashes series with England.
The left-arm quick has been battling pain in his right ankle since bowling on day one in Cardiff and showed great courage to get through 16 overs in England's second innings on Friday to finish with 2-60.
With only three days between the scheduled close of play on Sunday and the start of the Lord's encounter, Starc could face a race against time, with Peter Siddle in line to take his place should he not be fit.
Michael Clarke's side face an uphill task to avoid defeat in the opening Test, needing 412 batting last on a pitch that is showing some signs of deterioration at Swalec Stadium.
With Ryan Harris forced to retire last week due to a knee injury, the tourists bowling stocks are already stretched and the loss of Starc, who finished with match figures of 7-164, would be a hammer blow, especially if they are defeated in the Welsh capital.
"This is a real concern for the Australians," Former Australia captain Ricky Ponting said on Sky Sports. "There's obviously something going on there with the ankle."
The full extent of Starc's issue is yet to be revealed by Cricket Australia, but the NSW speedster has a history of bone spurs and underwent surgery ahead of the 2013 series.
England batsman Ian Bell, who was dismissed by Starc in the first innings, said he realised the 25-year-old was in pain but said he hadn't noticed any loss of pace when facing him.
"He looked in some discomfort ... but you'd expect someone - well any of the Aussie bowlers are going to keep running in.
"That's what he did and even if he was going through pain, he didn't really show it on the field. That's what you expect from those guys."
England were dismissed towards the end of day three for 289 in their second innings, leaving Australia chasing an Ashes record fourth-innings target of 412 for victory.