Turnbull played 8 games for City in 2007. The keeper, now 24 has been at Middlesbrough since he was 17. He's had 6 loan spells away from the Riverside but got a decent run in the first team early last season.
Now he's bagged a dream move to Stamford Bridge.
Another former loan player, Eddie Johnson, has been offered to Crystal Palace on loan. The American still has two years to run on his contract at Fulham but his agent is looking to get him loaned out again.
Palace boss Neil Warnock said: "We've had a phone call about him from his agent - but we don't know if we are going to follow it up. It's an option."