He was seriously considering an offer from Noel Murphy, then Ireland's chairman of selectors, to align himself to Ireland where he had a family history on his mother's side.
But 24 hours later Rowell called and the rest is history, right through to last year's triumphant World Cup final and beyond.
Life after the World Cup sees Dallaglio preparing to lead England against Ireland in his second reign as captain following the international retirement of World Cup-winning skipper Martin Johnson.
But, explaining how it could all have been so much different if Rowell had not made his timely intervention, Dallaglio recalled: "It came at a time when getting into the England team was very difficult because there were so many good players around - not that it gets any easier.
"I gave it very serious consideration but it didn't take very long for Jack Rowell to pick up the phone, less than 24 hours. I don't believe he knew about the Irish interest but if he hadn't phoned who knows what might have been.
"I went on the tour to South Africa and that was the end of the story."
Dallaglio, who was also qualified to play for Italy through his father, has spoken to Murphy about it many times since.
"I captained England in Dublin a few years later and sat at the top table with Noel Murphy and we had a laugh and joke about it because I could have been sitting on the other side of him," he said.
But the skipper will have no split loyalties when England defend their record 22-match winning run at Twickenham on Saturday.
No international team has ever strung together that many victories at a single venue but he said: "It's not something we dwell on as a team. This team just wants to win the next game and in doing that you can add to whatever record other people keep their eyes on.
"We certainly don't have any reason to be complacent. Every one of them have been pretty much hard-fought wins. We have huge respect for the Irish team but, in saying that, we have a huge amount of belief in our abilities.
"We know we are going to have to play to a man to the limit but that is something which excites us.
"Since the World Cup I've been very impressed with the way we've prepared for games.
I've been really pleased with the attitude of each of the players and the way they have responded to everything that has been asked of them, mentally and physically.
"I believe that physically we have moved on from November and I've been very pleased with our physicality in the last two games.
"What we need to add to that now is a bit more intelligence and possibly think a bit more about the way we are playing and, when we create opportunities, being aware of where to take them and how to finish them off."
Although he does not believe that the mere figures of 22 successive Twickenham wins give England an advantage over the Irish, Dallaglio conceded: "We clearly go into this game with confidence and momentum and that in itself is quite a strong and healthy ingredient to have."