"Andrew Flintoff is in the Lancashire squad for Sunday's Totesport League match and will play - provided his ankle suffers no reaction from training today and tomorrow," a Lancashire spokesman said.
"Freddie has received clearance to play as a batsman only for the moment."
The England all-rounder, widely regarded as vital to the Test side's hopes of ending a run of eight straight Ashes series defeats, underwent surgery on his left ankle in February which prevented him playing in the One-day series in South Africa.
Flintoff, 27, has since being following a rehabilitation programme at Lancashire devised by the Old Trafford club's physisotherapist.
Injuries and selection decisions have meant that Flintoff has still to play a Test against Australia, the world's number one side, despite 45 England appearances in the five-day game.
Flintoff has scored 2,239 Test runs to date at an average of 32.44 with four hundreds and a best of 167 and also taken 110 wickets at 34.80 with a best of five for 58.