"I got the injury quite early in the JP Trophy game with Macclesfield and at the time I thought I was only going to be out for a week to 10 days," he said.
"But after is settled down it was worse than I first thought and has kept me out for more than three weeks.
"Any injury, whether it keeps you out for three to four days or out for three to four months, is frustrating.
"I pulled my groin and I first thought about 10 days, but now it turns out it's been nearer a month."
And Valentine has refused to rule himself out of tomorrow's game at Moss Rose.
"At the moment I'm not sure," he added. "I'd like to be involved, but I don't know whether the manager thinks I've had enough time back from the injury or not. I suppose I'll just have to leave it up to him.
"I've not had any kind of a reaction. I've been running a few days this week already, but today is the first time I've been back playing football with the rest of the lads and everything went really well."