The 43-year-old becomes bowling coach at Grace Road after saying goodbye to New Road
Matt Mason has swapped Worcestershire for Leicestershire, leaving New Road after 17 years' association.
Mason has moved to Grace Road as bowling coach, having first signed for Worcestershire as a player in 2001. He had been due to take on a role as second XI coach at New Road in 2018.
He said: "I am really pleased to be coming to Leicestershire County Cricket Club. I'm excited by this new challenge and it will be great to work alongside Nico [Paul Nixon], Sads [John Sadler] and the rest of the backroom team and players."
"I have had 17 fantastic years at Worcestershire and experienced a lot as a player and a coach and will always retain great memories of the club.
"I have had a great relationship with members, supporters, players, coaches and staff and made some great friends. There are some fantastic things to cherish – as a player two Lord’s finals, winning the Pro40 League, a couple of Dick Lygon Awards at the Awards Evening.
"Then as a coach, the joy of a few promotions and working with the fast bowlers of which the current young group have fantastic potential.
"Worcestershire will always be close to my heart, I am going to continue to live in Worcester and I wish the club well – but now I am looking forward to the fresh challenge at Leicestershire."
Leicestershire head coach Paul Nixon said: "Matt [Mason] is a very good bowling coach with lots of experience of both county cricket and working with the ECB. He has helped to develop a number of very good young seam bowlers in his time at Worcestershire CCC.
"I know that Matt is the perfect fit for our coaching team and our bowlers will enjoy working alongside him. It’s great to have Matt on board with us and he will offer valuable knowledge and expertise to our bowling group."