"The timing is unfortunate because people will draw conclusions but they are wrong in this instance," he said.
"If I am honest, one or two players have let him down recently and they need to look at themselves because to a degree they have cost the manager his job."
The club announced on Thursday that one player had been fined two weeks wages with two others warned about their future conduct.
Sheridan's departure comes after Saturday's 6-2 defeat by MK Dons which saw the club slip to eighth in the League One table.
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