Wasps have announced that rugby director Dai Young is stepping back from first-team duties "for an interim period" at the Gallagher Premiership club.
Former Wales prop Young, 52, has been in charge since 2011.
Wasps are currently ninth in the Premiership after nine games, while they made a pool stage exit from this season's European Challenge Cup.
Wasps issued a brief statement which said: "Director of Rugby Dai Young will be stepping back from first-team duties for an interim period.
"Lee Blackett will step up to interim head coach. Further announcements will be made in due course."
Wasps' next league game is away against Leicester on Saturday.
They have lost six of their Premiership matches this term, winning just two of the last four.
Young enjoyed a successful playing career with Swansea and Cardiff.
He won 51 caps for Wales and played in three Tests on the 1989 British and Irish Lions tour to Australia.
Wasps have not won a major trophy since lifting the league title in 2008.
Young, though, did lead them to the 2017 Premiership final, when they were beaten 23-20 by Exeter after extra-time at Twickenham.