"Today is the last time I will be at Welford Road as a Tigers player," said the 30-year-old in the match programme for Saturday's Zurich Premiership game against London Wasps at Welford Road.
"And I'd like to thank everybody associated with Tigers for the tremendous support they've given me over the last five-and-a-half fantastic years.
"I'm also extremely grateful to Dean Richards and the Board of Directors for letting me take this opportunity to play in Perpignan, and to release me at this stage so that I will qualify to play for them in the Heineken Cup.
"I'm disappointed that a knee injury has prevented me from playing for the last month, especially as it is a difficult time for the club. Now is the time for everybody to get right behind the team – the better the support, the better they will play."
Director of rugby Dean Richards added: "Today we bid farewell to Tim Stimpson who is moving on to Perpignan after five-and-a-half years at Leicester.
"We'll be sad to see him go, but life goes on, and this was too good an opportunity for him to miss.
"Tim is leaving a couple of weeks earlier than expected as Heineken Cup rules mean he has to be registered for them by next week. It's a shame that his knee injury has kept him from playing for the last few weeks – I'm sure he would have liked to have gone out on a high in front of the Welford Road crowd."
Stimpson won 19 England caps between 1996 and 2002.