Longer, 20, had nominated the Hawks as his club of choice after telling the Lions he wanted to return to his hometown of Melbourne after two seasons at the Gabba.
But McEvoy's surprise deal to the reigning premier has thrown a cloud over any potential move.
Playing behind Matthew Leuenberger as the second ruck in Brisbane, Longer hoped to get more opportunities with a move.
But the Hawks are now well stocked with McEvoy and back-up forward options David Hale and Jarryd Roughead to relieve him.
Despite giving up its first round pick, and Shane Savage, to secure McEvoy, Hawthorn recruiting and list manager Graham Wright told AFL.com.au's Gillette Trade Radio the Hawks were still keen on Longer.
They still have the likely first-round compensation pick for Lance Franklin's move to the Swans as a trading tool.
But the Lions are hopeful the latest move will convince Longer, who they selected with the number eight pick in the 2011 NAB AFL Draft, to stay.
"Our preferred option has always been to retain Billy," Lions talent manager Rob Kerr said.
"The McEvoy trade will hopefully convince Billy that the best option for his football is to stay in Brisbane.
"We're prepared to continue working with Billy and his family to convince them that he can be successful in Brisbane."
Kerr was also hopeful some savvy words from new coach Justin Leppitsch would help sway Longer to stay.
"Justin's already expressed that there's an opportunity for him in the senior team next year as part of his game plan."
Twitter: @AFL_mikewhiting
