Former Ireland coach Warren Gatland has confirmed that he has spoken to Wasps director of rugby Nigel Melville about joining the club as forwards coach.
"Nigel (Melville) and I have had a few conversations and we're a reasonable way down the road," said Gatland.
"But, until everything is signed, there is nothing official. I would say everything should be sorted out by the end of the week."
If terms can be agreed he is expected to work alongside Melville and defensive expert Shaun Edwards, the former rugby league star.
Melville, whose side are struggling near the foot of the Premiership and were overpowered by Munster in the European Cup, said: "We haven't sorted a deal out yet but we're optimistic. Warren wants to come here, and we'd love to have him."
Meanwhile, Castres are facing an injury-crisis ahead of their top-of-the-table European Cup clash against Munster in France on Saturday.
Following their 37-26 win over Bridgend at the weekend, coach Remy Tremoulet has injury concerns about key players Frederic Laluque (knee), Romain Teulet (head) and Rafael Ibanez (knee). France hooker Ibanez admitted he is struggling to regain fitness.
Winger Christophe Dominici is likely to miss the whole of France's Six Nations campaign after dislocating his right shoulder playing for Stade Francais against Treviso.
