But in January 2005, Reddan asked for a new contract only to be told he would have to wait until June for a definite answer. And it was at that point that what he describes as the biggest coincidence of his life unfolded.
"I was devastated but I went home and the phone rang," said Reddan.
"It was Shaun Edwards asking if I wanted to go to Wasps in the English Premiership.
"It was the biggest coincidence of my life and I said yes straight away. At that age you don't want to be waiting around. I spoke to Munster and left on good terms.
"You grow up wanting to pull on that red jersey and I wanted to give it a go. But it didn't work out and that was that"
From there Reddan's career sky-rocketed and in 2008 he picked up the Premiership and Heineken Cup double.
Now, after playing his part in Leinster's Heineken Cup triumph last weekend, Reddan is on a personal crusade to complete another historic double by beating Munster in the Magners League Grand Final.
"Being from Limerick my family will be there and it will be great to play in front of them.
"But the game overtakes that , it's a huge occasion. A lot of Leinster fans are travelling down and Munster finished top of the league. They will be determined to finish on a high.
"It's a big challenge, huge, but hopefully it's one we will rise to. It's always good to have these challenges. Being here is one thing but doing it is another."
Aside from the personal emotions of facing his home province, Reddan insists it is easier to focus on a game against the Limerick-based outfit.
"It's a bit easier to focus on the game itself this week rather than what's on offer," added Reddan.
"There's that rivalry great that's always there between the two sides. It doesn't matter what game it is, against Munster it will be tough.
"They've done very well to finish top of the league, they've been consistent home and away and with different teams on the pitch.
"We want to win and obviously they also want to win. Us going there as Heineken Cup Champions will only add to that.
"It will certainly be a big one and hopefully we can rise to the challenge."
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