Nick Kennedy is expected to join Harlequins after leaving European champions Toulon.
Kennedy asked to leave the French club for 'personal reasons' and Toulon agreed, and have already replaced the former London Irish lock by signing New Zealand star Ali Williams.
Harlequins need a second row forward to replace Olly Kohn, who has forced to retire from the game because of a shoulder problem.
Kennedy, who spent 11 years at London Irish before moving to Toulon, is understood to have been lined up as Kohn's replacement at The Stoop .
Kennedy, 31, struggled to settle in the south of France and last season admitted he may have made a mistake moving to France.
But he was a success on the pitch, helping Toulon to win the Heineken Cup with a 16-15 victory over Clermont Auvergne in Dublin, though they then lost the Top 14 final to Castres.
Kennedy was grateful that Toulon president Mourad Boujellal accepted his request for an early release.
"Winning the Heineken Cup was a career highlight for me and I'm still gutted we lost the Top 14 final," Kennedy tweeted.
"I'm very lucky to have played with some of the world's best players and more importantly top guys, I'll be watching and supporting from here.
"Thank you to the president for releasing me for personal reasons."