Earing, who had struggled with an Achilles issue over the summer, pulled up in last weekend’s loss to Tranmere Rovers and was forced off shortly into the second half.
The 23-year-old midfielder has since been assessed and will be out for up to 12 weeks
“The injuries, I’ve not been able to play my best team because they’re injured. When we get one back, another one seems to go out,” said Flynn, whose side were out to get a much-needed win at Stockport County today.
“Jack Earing is out now for possibly 12 weeks. That’s another kick in the teeth. It’s relentless.
“I’ve never known anything like it. It’s frustrating, it’s painful, but we’ve still got to step up.
“We’ve got be a little bit more switched on than we have been.”
Earing joins Conor Wilkinson, Joss Labadie, Joe Riley, Oisin McEntee and Adam Przybek in the treatment room.
Walsall are struggling with a couple more unspecified issues, too, as Flynn added: “There’s more bad news on the injury front but I’ll keep one or two of them quiet.
“Another thing I will mention is that Joe Foulkes has fractured his ankle out on loan (at Kidderminster Harriers), so even our loan players are getting injured.
“There’s not been one muscle injury, touch wood, so it shows we’re not over-training them or risking them in that way.
“They’re all completely freak injuries and I’ve never known anything like it.
“There’s another one or two struggling. In terms of players coming back, the answer is no in terms of the next few weeks.
“But Oisin did join in non-contact which was really pleasing to see.”