Danny has played for the senior side at Rodney Parade since 2006, overcoming a serious neck injury in 2007 which threatened his career.
The RBS 6 Nations player of the series has been a key player for the Region and the Dragons were keen to retain him within their ranks.
"We are obviously very disappointed that Danny has decided to leave the Dragons," said Dragons Director of rugby Rob Beale. "He has been a key part of our set up for several years and is popular with both the players and the coaches."
"I can assure our supporters that we did all that we could to retain Dan's services but we simply cannot compete with the offers which have been put on the table."
There will be no further comment from Danny on this issue at this time.
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