Her decision to step down from her job as the head of the WindsorEssex Economic Development Corporation has fuelled speculation that her name will be on the ballot in the upcoming federal election.
The Liberals have yet to choose a candidate to run in the riding that Pupatello used to represent at the provincial level. That makes the timing perfect for her to make a political comeback.
Brian Masse has held the Windsor West seat for the New Democrats since 2002. He won the seat in a byelection and has since been re-elected four times.
At the provincial level, Pupatello held the Windsor West riding from 1995 to 2011. She was elected four times in a row and served as a cabinet minister in the government led by former premier Dalton McGuinty.
She later made a run at becoming the leader of the provincial Liberals, but lost to Kathleen Wynne, who then became Ontario's premier.
If Masse and Pupatello were to go up against one another in Windsor West, it would be quite a race.
'Speculation in the air'
So far, Pupatello has not said yes or no to running for a seat in Parliament.
"People will look for a candidate wherever they think there is a name that is known. That is what parties do, so it's not unusual that they would think to ask me, and they have done so since I left politics in 2011. It hasn't stopped," Pupatello said earlier this week, after it was announced that she would be leaving her position with the economic development corporation.
Pupatello also said she has not closed the door to political life.
Lydia Miljan, an associate professor of political science at the University of Windsor, however, thinks it is unlikely that Pupatello will run.
Acknowledging that a Pupatello-versus-Masse ballot would be a clash of titans, Miljan believes that Masse would win.
"He's the incumbent, he always enjoys a strong majority," Miljan told CBC News in an interview on Tuesday.
"But more importantly right now, the NDP are leading the polls federally, and so it would make very little sense for people in Windsor West to have been putting all their support behind the NDP while they were clearly in opposition and here is their first chance that they even have a glimmer of hope of forming government."
Doug Sartori, the vice-president of the Windsor West Federal Liberal Riding Association, told CBC News that the party has yet to nominate a candidate in the riding.
While he would not identify the names of any potential candidates for Windsor West, Sartori acknowledged that Pupatello's departure from her job has "got people talking and there's lots of speculation in the air."