Carlisle and Pitman joined Wasps at the start of the 2013/14 season from Worcester Warriors and Rotherham Titans respectively.
Speaking about Carlisle’s departure, Wasps’ Director of Rugby Dai Young said: “Joe is a talented player who I am sure will do a good job for whichever club he decides to join from here. We wish him the very best for the future.”
Carlisle added: “I would like to place on record my thanks to Dai, Stephen Jones, all the staff and of course the players at the club. I have been fortunate enough to have made friends for life during my time at Wasps and I'm sure that great things are just around the corner for the Club.”
Pitman, who has represented Wales at U16, U18 and U20 level, will join Scarlets next season.
Pitman said: “I’ve thoroughly enjoyed my time at Wasps. Dai Young and the coaching team have been really supportive and I’ve fallen back in love with rugby here in such a professional yet personable environment."
“The back row is an extremely competitive area for Wasps and I have enjoyed playing alongside and learning from the players here. However, I’ve reached the age where I need to push on and play more regular first team rugby in order to develop my game."
“I’m excited about joining Scarlets, who also have a strong back row, and I’m looking forward to the challenge of competing for a place in their starting lineup.”
Dai Young said: “Rory is a talented player who is a destructive ball carrier. He was unlucky to miss a large chunk of the season after tearing ankle ligaments and he really impressed me with his attitude and commitment to return from injury.
“I fully understand his desire for more regular game time, which is difficult to guarantee here due to the calibre of back row players we have fighting for a starting spot. We all wish Rory the best as he returns to Wales to play for Scarlets.”