Davidson joined Preston from Leicester in the summer of 2004
Preston defender Callum Davidson says he is expecting to return to first-team action by the end of October.
The 32-year-old has featured just twice as a substitute since injuring the posterior cruciate ligament in his knee in August's win over Crystal Palace.
He told BBC Radio Lancashire: "Three weeks is the best time scale we can put on it.
"That gives me enough time for rehab and to try and solve the weaknesses that was causing it to happen."
Normally with me it's muscles or groins. For me to have a knee injury is strange
Callum Davidson
After featuring in 40 league matches last season, Davidson has started just two of the first 10 matches this term, despite brief comebacks against Coventry and Burnley as a substitute.
"On Friday morning I collided awkwardly with someone and it aggravated the same injury again," he said.
"I carried on training but woke up on Saturday and it wasn't great so we had to reassess it again.
"This time myself and the physio have got to make sure I don't have any set-backs again.
"Normally with me it's muscles or groins. For me to have a knee injury is strange."
Davidson's latest injury blow has meant that his return to the international scene with Scotland has had to be put on hold.
"The manager [George Burley] phoned me and just said get yourself fit and we'll see what happens for the next game.
"At least he took the courtesy to phone me and let me know what was happening," he added.
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