Andrew Flintoff's latest comeback has been delayed on the advice of Lancashire's medical team.
The England all-rounder was due to return to action on Monday in a one-day match for the county's second XI against Yorkshire.
However, the 32-year-old, who has not played since undergoing knee surgery last August, could still feature in a three-day fixture against the same opponents that gets underway on Tuesday.
Flintoff went under the knife after helping England regain the Ashes last summer in his final appearance in Test cricket.
He then needed a second operation on his problematic knee in January before returning to full-time training towards the end of June.
"Nothing's happened it's just a case of them (medical staff) being happy with the level of conditioning around the knee and his general body so that when he does play he's at minimum risk of getting injured again," Lancashire coach Peter Moores told The Guardian.
"It's been a long rehab so far, and what they're making sure is that it's not rushed. It's got to be right.
"They think, at the moment, that he's not quite ready and ruled him out of the one-dayer, (because there is) slightly more violent running round in a one-dayer.
"They'll assess where he is for the rest of the week."