"It took me a long time to come to a decision about leaving somewhere that I've called home for seven years, I've been here a long time in the senior environment.
"I'm going to concentrate on the rest of the season with the Scarlets and hopefully finish the season with a bang.
"As a player you owe it to this club, you can't just say you're not committed anymore. For me personally nothing changes, I'll still be as committed as ever. We have to finish this season well, we've got 13 out of 15 points in the last three games and we need to maintain that for the next couple of weeks."
Turnbull will start in the backrow this evening alongside captain Rob McCusker and Scottish international John Barclay as they take on Ulster at Ravenhill.
Looking forward to the all-important clash which comes after three wins from the last three RaboDirect PRO12 rounds, Turnbull said: "I think we're all pretty confident, we've had a good couple of weeks and a good couple of wins."
Turnbull is fully aware of the threats that Ulster bring, he went on to say: "You've got to go hard against them and nullify a few of their key players, especially the likes of Pienaar and Nick Williams. If you keep those guys relatively quiet you can probably keep on top. If we can do what we did against Munster with our forward pack we can really set a stall for the backs."