Tommy has confirmed he has turned down a new deal to stay in Scotland and is heading home to New Zealand after six years.
Tommy, who missed the last few matches of the season with an ankle injury, said: "I was offered a fresh contract but it didn't measure up to what I was looking for. Under the circumstances I have decided to make arrangements to go back to Waikato."
Dave had kept his departure quiet until after Friday's victory over Borders at Hughenden.
He said: "I am looking at other options because I've heard nothing from the Glasgow management. That's the way things work in the pro-game. In all honesty, I have known for a while that I would not be hanging around and I have also given up hope of being back in a Scotland jersey for the World Cup.
My agent has a few possibilities in the pipeline and it is a case of weighing up all the situations on the table. It is also time for me to look ahead for when rugby won't be the main feature of my career. I have never had any regrets about coming to Glasgow from Bath. It had been the right time for a change and I have enjoyed it."