But he returns to Sardis Road in the new season boasting a wealth of experience and increased appetite for the game.
"I felt the time was right to make a move, and having loved my time with Ponty earlier in my career, it was the club to which I wanted to return" said the Wales Sevens stalwart.
"When the opportunity came along to do so I jumped at it, and I can't wait now for the season to get underway and be back playing in the black and white."
Shellard has been held back by a calf strain in Ponty's pre-season preparations and he is well aware of the competition in the back-row.
But he is determined to make a major impact during his second stint with the Principality Premiership champions.
"I realise that there is stiff competition in the back row here. With Wayne O'Connor the master craftsman and youngsters like Calum Thomas and Tom Hetherington coming through my first task will be to claim a place in the starting line up.
"I hope to make my mark pre-season and be able to help the club off to a good start in the league.
"There are high standards to maintain here at Ponty, and the whole squad is focussed on retaining the league title, regaining the Welsh Cup and improving on our status in the British & Irish Cup.
"There is so much to play for and if I can make a contribution to the club's success it will more than justify my decision to come back here."