Middlesbrough midfielder Julio Arca could be out until December after suffering knee ligament damage in Saturday's 2-2 draw with Sunderland.
Southgate told the club's official website: "We have had some more positive news this afternoon.
"Both Mido and Tuncay have gone for scans and there's no significant damage, and both have a chance of playing on Sunday.
"However, the injury to Julio looks more serious. It's the medial ligament in his knee and it looks like it will be at least two months."