The pace bowler has been plagued by problems in recent times, including a succession of stomach-based issues.
The 23-year-old is unlikely to feature before the T20 Blast, which for Yorkshire begins on June 10.
Martyn Moxon, the Yorkshire director of cricket, said: “We’ve been investigating what might have been causing this kind of unusual trail of stomach muscle injuries that Matthew has been suffering from lately.
“We’ve been looking at a lot of footage and we may have found something that’s crept into his action that might be causing it.
“Hopefully this little bit of evidence is the answer, and he can put to bed this particular type of injury going forward and it can be easily rectified and he doesn’t have to worry about it again.
“It’s frustrating for him because he got back to playing second team cricket recently and bowled beautifully down at Essex, where he got three wickets in his first spell and bowled with good pace, but then he felt the stomach injury again.”
Fisher started the County Championship season at home to Glamorgan but experienced abdominal problems during that game.
He has suffered from injuries throughout his career having also had hamstring, side, toe, thumb, back and shoulder issues.
“He’s had some very bad luck,” added Moxon, “and it’s obviously very frustrating and disappointing for him.
“He’s the kind of lad who is desperate to do well, and picking up all these injuries is obviously not good for him.
“You talk about mental health, and it’s not good for his mental health, that’s for sure.
“He keeps having to get himself fit and thinks that he’s ready, and then he picks up another injury, which is obviously all very depressing for him.”
Commenting on Fisher’s likely return, Moxon said: “It’s difficult to put a timescale on it at the moment.
“I think that realistically we’ll probably look to target him being ready for T20 hopefully, but it’s too early to say exactly when.
“The main thing is that we don’t rush it and that we get him right because we all know the quality that Matthew possesses.
“Hopefully the problem has now been identified and he can put this particular issue to bed.”
No play was possible on day one of the return fixture against Glamorgan in Cardiff.
Heavy rain overnight left puddles on the Sophia Gardens outfield, and although conditions were dry for much of the morning, heavy rain returned in the afternoon, with the call-off coming at 2.45pm.
It meant that Harry Duke, the 19-year-old wicketkeeper, had to wait to make his first-class debut having been picked in preference to Jonny Tattersall.
Joe Root was also left waiting to make his final Championship appearance before the international season against a Glamorgan side for whom his younger brother Billy plays.
Meanwhile, Moxon has confirmed that Yorkshire hope to have Dawid Malan available for their next Championship fixture after this week.
Yorkshire have a 10-day break between games before returning to action against Lancashire at Old Trafford on May 27, when Malan would effectively slot in for Root.
The England T20 batsman had been away with Punjab Kings in the Indian Premier League, but that competition has now been postponed due to the Covid-19 situation in that country.
“Hopefully we’ll have Dawid back after the Glamorgan game,” said Moxon.
“It will be a big boost, certainly, particularly with Rooty not being available.”
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