The deadline to nominate directors for election at CSX's annual meeting was Friday, but the company announced it is extending the deadline until Feb. 24.
That seems to confirm reports that CSX has been negotiating with Harrison to avoid a proxy fight.
Harrison retired from Canadian Pacific last month and the Wall Street Journal reported he was seeking to replace Michael Ward as CSX chief executive officer.
Ward has not given any indication he is ready to leave CSX.
Even if he doesn't become CEO, Harrison could be looking to nominate new directors to CSX's board.
He has a reputation for cost-cutting and improving operations at Canadian Pacific and in his previous role as CEO of Canadian National Railway Co.
The Harrison rumors have sparked a jump in CSX's stock price, with investors speculating his involvement could increase CSX's earnings.
As rumors persist that CSX Corp. is negotiating with former Canadian Pacific Railway Ltd. CEO Hunter Harrison to possibly take over the Jacksonville-based company, CSX on Friday extended the deadline to nominate directors to its board.