LONDON, June 30, 2023 (BSS/AFP) - Nathan Lyon's future on the Ashes tour is uncertain after he arrived at Lord's on Friday on crutches, as the Australian camp reported the bowler had suffered a "significant calf strain".

The off-spinner limped off during Thursday's second day of the second Test after pulling up, having run in from the boundary while fielding.

The 35-year-old, appearing to wipe away tears, eventually limped around the boundary edge towards the dressing room while a staff member supported him.

Lyon, appearing in his 100th consecutive Test, joined his team-mates at Lord's on Friday morning, using crutches and wearing a compression sock.

It now seems unlikely that he will play any further part at Lord's, while a three-day break before the third Test at Headingley means it would be remarkable if he featured in Leeds.

"Nathan Lyon has been diagnosed with a significant calf strain," a Cricket Australia spokesman said on Friday.

"He will require a period of rehabilitation after this match is concluded. A decision regarding his availability for the remainder of the series will be made at the conclusion of the game."

Australia batsman Steve Smith was concerned when asked Lyon's injury after Thursday's close.

"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."

Australia have a trio of part-time spinners -- Smith, Travis Head and Marnus Labuschagne -- who may now have to cover Lyon's absence at Lord's.

And should Lyon be ruled out of the third Test, reserve spinner Todd Murphy could be called up at Headingley.

Earlier on Thursday, Lyon had dismissed Zak Crawley to claim his 496th Test wicket and ninth of the series.

Lyon's appearance at Lord's made him only the sixth man to play in 100 consecutive Tests and the third Australian after Allan Border and Mark Waugh.

His 496 Test wickets place him eighth on the all-time list and fourth among spinners.

Shane Warne and Glenn McGrath are the only Australians to have taken more Test wickets than Lyon.

Ashes-holders Australia, bidding for a first Test series win away to England in 21 years, are 1-0 up in the five-match campaign after a two-wicket win at Edgbaston.