The 36-year-old flanker won 94 caps for Wales and also played club rugby in France and England.
He had intended to spend the 2008/09 season predominantly in a coaching role with the Newport Gwent Dragons but injuries saw him called into action at the beginning of the campaign.
His form was so impressive that he remained a key part of the region's on-field plans until a knee injury brought a halt to his run in the side.
Dragons head coach Paul Turner has been full of praise for his player coach's contributions this season but he admits that Charvis' impressive playing career looks like it has already come to an end.
"Colin has had an operation on his knee," said Turner.
"He's at the end of his career and he's clearly not fit.
"I wanted him to concentrate on his coaching with us this season but his performances were so brilliant early in the season, I couldn't leave him out.
"He's been great for the region."