The Canadian military's second-in-command has announced his surprise resignation — and is reportedly linking the decision to an aborted attempt to reinstate Vice-Admiral Mark Norman into the position.

Lt.-Gen. Paul Wynnyk's decision to leave the Canadian Forces, effective Aug. 9, represents the latest blow to the military, whose senior leadership has been in a state of perpetual upheaval since Norman was suspended in January 2017.

The Defence Department released a statement announcing Wynnyk's resignation late Tuesday, nearly a year after the former army commander took over the vice-chief of the defence staff position on a permanent basis. A replacement has not been named.

In the statement, Wynnyk is quoted as saying he had considered the decision for several months and decided with his wife that it was time for their family to be reunited. Wynnyk has maintained a permanent home in Edmonton.

"I would like to thank the chief of the defence staff, Gen. Jon Vance, for the confidence he showed in me when he appointed me as the vice-chief and for his leadership of the [military] during what have been challenging times recently," Wynnyk said.

Yet while Wynnyk attributed his decision to resign to his desire to return to his family, a letter obtained by Global News reportedly sent by the outgoing vice-chief of the defence staff to Vance suggests different reasons.

In it, Wynnyk writes that Vance asked him shortly after the breach-of-trust case against Norman was dropped in May to step down before reversing course following the government's settlement with Norman.

But Wynnyk says when Vance asked him to stay on, he declined.

In a statement posted on Twitter on Tuesday evening, Vance bid farewell to Wynnyk "with deep gratitude for his life of service and our close friendship for nearly 40 years," he said. "We will miss you in uniform, old friend."

Yet the move is likely to put added pressure on Vance, who some have accused of contributing to Norman's two-year legal ordeal by suspending the popular naval officer upon learning the RCMP was investigating him in 2017.