The New Zealand international is a free agent in June and unless a new deal can be agreed he'll be in contract limbo when the Kiwis kick-off their opening World Cup fixture against Slovakia.
If Middlesbrough claim a play-off final berth Killen will join up with his international teammates a week late but he insists his contract situation and the upcoming tournament will not distract him from the business in hand.
Since making the switch from Celtic the 28-year-old has proved a useful addition to Gordon Strachan's attacking options, netting three times in his 15 appearances.
Strachan knows Killen from their time at Parkhead and insists his decision on whether to offer the striker a new deal will be based on his long-standing knowledge of the striker's abilities rather than solely on his brief spell in red and white.
Strachan said: What has Chris Killen got to do to secure a new deal here Nothing really, I know what Chris does and doesn't do. I'll be speaking to his people once we get this weekend out of the way. They have already been in touch with me.
Killen was an unused substitute in last Saturday's victory over Sheffield Wednesday but is pressing for a recall this afternoon and believed it could prove useful to his cause that Strachan knows him from Celtic.
It can only help,'' he said.
This is the longest run of games I've had under the gaffer starting games so hopefully he's got a better idea of the player I am.
You'll have to ask the manager if I've done enough to earn a new contract, he's the one who makes the decisions.
I don't think it's too much of a problem I've got such a great summer to look forward to, that's taken over a lot of the contract things. I'm just looking forward to the next three games and seeing where we can go from there and then the World Cup.
I'd like to be sitting here and knowing what I'm doing next season and having that settled, but it'll have to be left to the end of the season.'' Given the choice of helping Boro grab a play-off spot or helping New Zealand reach the knock-out stages of the World Cup, Killen replied: That's a tough one. I'd hope both. I'm more towards the club football at the moment because that's the priority right now but I'll worry about the World Cup when that comes along.
We want to get straight back up. We all want a shot at the Premier League and this club deserves to be there. If we can help out we'll do our utmost to get there.
I hope I'll be playing this weekend, I was disappointed not to be playing last weekend.
I want to be playing for sure with only three games left so I want to end the season on a high.