Nathan Lyon arrives on crutches as calf injury puts Ashes role in doubt

The Australia spinner had to be helped off the pitch on Thursday evening after pulling up with an apparent calf problem as he fielded in the deep.

The 35-year-old, playing his 100th consecutive Test, looked distraught as he hobbled around the boundary edge with question marks immediately raised over his continued presence on the tour.

He joined his team-mates at the ground on Friday morning, but his reliance on crutches and the presence of a compression sock told its own story.

It now seems almost impossible that he will be play a role in ongoing match, while the three-day turnaround before the third Test at Headingley means that must be highly unlikely too.

Cricket Australia's medical staff are monitoring Lyon but offered no official update as he battles to save his series.

Steve Smith admitted he was not optimistic when asked about the injury at the end of day two.

"Obviously it didn't look good," he said.

"I mean it doesn't look ideal for the rest of the game. I'm not sure how he actually is, but if he is no good, it is obviously a big loss for us.

"Fingers crossed he is okay but it didn't look good."

Australia have three part-time spinners who may be asked to pick up a share of the workload over the next three days, with Smith joined by Travis Head and Marnus Labuschagne, but should Lyon be ruled out of the next match Todd Murphy is in line for promotion.