Owen Farrell is in a race against the clock for the first Test after a training ground injury ruled him out of the next British & Irish Lions tour match against the Maori All Blacks.
The England first-five, who starred in the Lions win over the Crusaders, suffered a grade-one quad strain.
It would be a monumental blow to the Lions squad if Farrell was sidelined for any longer than expected with the 25-year-old an integral part of Warren Gatland's first Lions side, forming a key partnership with blockbusting England cross-coder Ben Te'o.
Named on the bench to play the Maori All Blacks, Farrell will be replaced by Welshman Dan Biggar for the clash in Rotorua.
Farrell will have one more chance to prove his fitness before the opening Test against the All Blacks with the Lions set to take on the Chiefs in Hamilton on Tuesday 20 June.
British & Irish Lions team to face the Maori All Blacks
15. Leigh Halfpenny 14. Anthony Watson 13. Jonathan Davies 12. Ben Te'o 11. George North 10. Johnny Sexton 9. Conor Murray 8. Taulupe Faletau 7. Sean O'Brien 6. Peter O'Mahony (capt) 5. George Kruis 4. Maro Itoje 3. Tadhg Furlong 2. Jamie George 1. Mako Vunipola.
Res: Ken Owens, Jack McGrath, Kyle Sinckler, Iain Henderson, Sam Warburton, Greig Laidlaw, Dan Biggar, Elliot Daly.