Nico Hulkenberg left the team for Sauber at the end of 2012, with several names - including former driver Adrian Sutil and reserve Jules Bianchi - being linked to the vacant seat.
"I am surprised there has been nothing yet. The team have said they will announce it in good time as to where they are going to be, and I have to respect that", he said at the Autosport Show in Birmingham.
The Scot added that the identity of his team mate does not concern him.
"As long as the team-mate is fast, and has respect for me and is a team player, that is all I can ask for".
"It is when you get somebody who only has their own ambitions in mind... nowadays in F1 you need to work as a unit and you can see it gets a bit political, and that is how the sport is driven," he added.
Di Resta, who finished a best of fourth in Singapore last year, believes that a stronger pre-season campaign is vital in 2013.
"We just need to ramp up the development. Last year we got stalled a bit towards the end of testing. We started very well but people were bringing developments and we didn't do that".
He also reckons the Silverstone based team should be targeting podiums this year but consistency is also a major target.
"Vijay [Mallya, co-owner] and the team are focused on achieving that. Our competitors, Williams and Sauber, they achieved that last year and we nearly did it, and the main thing we should focus on should be consistency."
"When we do get the chance to finish on the podium, we should understand why and repeat it the next week - that is the main thing."
Di Resta had his seat fitting at the factory on Friday, where the VJM06 is due to be launched on Friday 1st February.