Every single professional referee is monitored on a daily basis.
"Every single training session they do, everything is done on a heart monitor and downloaded to scientists and is analysed to see how hard they are working and whether they need to work harder.
"The Premier League is well aware of who's fit and who's not fit on a week-to-week basis.
"They know who is carrying injuries and who is able to ref games.
"I was in the Football League for 22 years and during that entire time I have never heard a referee be described as "unfit". It's just a thing that doesn't happen now because referees are so focused and so professional."
Gallagher is used to the pressures of refereeing at Old Trafford
The Football Association has written to Ferguson to ask for an explanation for the outburst, which came despite his side securing a draw with a dramatic injury-time equaliser.
And Gallagher, a former room-mate of Wiley, believes the veteran boss has let himself down in the manner of his accusation.
He added: "There's better ways to deal with things. If in the year 2009 you're an employee, you don't expect your employer to have a go at you in public.
"There are certainly avenues to go down. Sir Alex could have gone to the League Managers' Association for example.
"That way things are kept in house, as I believe they should be, and can be dealt with properly and effectively."
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