"I've really enjoyed my time at London Irish and am grateful for everything that the club has given me," he said.
West frustrated by Saints criticism
Meanwhile, Saints duo Alex Waller and Tom Mercey have both agreed new deals. And Doran-Jones could be about to leave Franklin's Gardens,
having joined in 2011-12.
"It's pretty common knowledge we're losing Soane and Brian to Racing Metro and I think we're losing Doran-Jones to Harlequins as well," West said.
"So it's three good, young props we're signed there and we're looking to add to those."
Waller, 22, is the only Saints player to have featured in every first-team match-day squad since the start of the 2011-12 season. He also won the club's Young Player of the Season award last year.
The Kettering-born senior academy graduate has made 78 appearances.
"It wasn't a hard decision to make," he said.
"My family are in the area, I've been playing here for the last four or five years and I feel that I have developed a lot as a player. Hopefully I've become an established member of the squad and can keep on pushing for a starting spot."
Mercey, 25, who is in his third season at Franklin's Gardens, has made 44 appearances for Saints and has also represented England Saxons.
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