A picture posted on social media of John Sheridan allegedly meeting Oldham Athletic officials in a coffee shop is at the centre of a possible complaint by Newport County about his departure.
The Exiles could report Oldham to the Football League over their conduct before Sheridan was appointed manager.
The picture of Sheridan seemingly talking with Oldham's chairman, Simon Corney, surfaced on Tuesday.
That has angered Newport, who believe it was before the clubs had spoken.
Sheridan has been manager at Rodney Parade for just over three months before switching to the Latics.
"In light of what we saw on social media, which was very disappointing, the club are considering [its] options," director Gavin Foxall said.
"We wish John all the best and understand his reasons for leaving.
"But the manner of his departure has not been right and we will talk further as a club about what, if any action, we should take."
Oldham's managing director Anthony Gee told BBC Radio Manchester that they had done nothing wrong.
"I want to be very clear, myself and Simon phoned Newport before we met John," he said.
"Newport might want to see it differently to save face. We have done it all properly."
Speaking to BBC Wales on Thursday, Oldham's chief executive Neil Joy said that the Latics "considered the matter to be closed".
Latics chairman Corney praised the Welsh club when announcing Sheridan's appointment.
"I would like to take this opportunity to add my thanks to Newport County who have dealt with this situation in a professional manner," he said.