And his teammates gave the prop a perfect send off, downing Connacht 24-9 as Hayes was replaced in the second-half to a standing ovation.
Nicknamed the Bull for his tenacity, you would think Hayes would find it hard to walk away from the game, but with the words of Keane still ringing in his ears from a meeting a few years back, the British and Irish Lion knew his time was up.
"Roy came in to chat to us and told us that nobody was bigger than the team, that you are only here for a while and that you should enjoy it while you can," Hayes told the Irish Examiner.
"He pointed out that he had seen great players come and go, that you had to give it everything you could, always appreciating that the end of your career would come some day.
"Even then he could see that his time was coming.
"I've been in this team now since 1997 and only Wally (David Wallace) and Rog (Ronan O'Gara) are still there.
"It's been a great 14 years or so and it was a tremendous way to wind it up.
"I hadn't expected the reception I got, the way the crowd cheered and so on, but I was very conscious that we had to win the game first and foremost. It would have been very much a damp squib had we lost.
"Of course, I'm going to miss it an awful lot. You find out an awful lot about yourself in a team environment, how you react to wins and to defeats.
"But when you leave here, there are other challenges to face and you can't do it in a comfort zone."
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