Paul di Resta has revealed that he could yet be involved in this year's Formula One campaign, and is merely waiting to put pen to paper to confirm a deal.

The Scot, who has strong Mercedes ties thanks to his involvement in the DTM touring car series, had been tipped as a possible candidate for a seat at Force India in 2009 following the Three Pointed Star's decision to provide Vijay Mallya's outfit with an engine and drivetrain package, but was overlooked when the Indian announced an unchanged line-up of Giancarlo Fisichella and Adrian Sutil before Christmas.

Despite the snub, however, di Resta remains confident that he will have some involvement in the top flight this year, whether as a race or test driver.

"I'm close to putting pen to paper on a deal - Formula One remains a possibility," he noted over the Christmas break.

What the former F3 Euroseries champion did not reveal, however, was where the deal may take him. With the only remaining race seats - at Scuderia Toro Rosso and, potentially, at a rescued Honda team - almost certainly out of the question, a testing role with either McLaren or Force India remains the most likely opening.

Pedro de la Rosa already fills one of two such seats at McLaren, with di Resta's Mercedes DTM stable-mate Gary Paffett also carrying out development work for the Woking team, while former Toro Rosso racer Tonio Liuzzi was on board at Force India in 2008. The Italian was retained by Vijay Mallya at the same time as Fisichella and Sutil were reconfirmed by the Silverstone operation.

Should di Resta sign a testing deal with an F1 team, he is expected to mount another assault on the DTM title, which he came close to winning last year after a strong late-season challenge to Audi's Timo Scheider.

"Next year? Well, who knows?" he wrote on his personal website on Christmas Eve, "I'm pretty close to putting pen-to-paper on a deal which will again have me racing in a car capable of winning races. As soon as the ink is dry, you'll be the first to know.

"I know there's been a lot of speculation recently regarding where I'm going to be racing next year and, to be honest, there's still a bit of talking to be done before I'll be able to confirm with you exactly what I'm going to be doing.

"One thing which is important is Formula One remains a possibility. I'm certainly not giving up on my dream of being on the grand prix grid for the opening race of 2009 but, if it doesn't happen this year, I'm confident it will happen soon afterwards.

"I've had a stunning 2008 and it's important my development continues through next year. Driving the McLaren-Mercedes in the two test sessions was a fantastic experience. But it was also a chance for me to show the guys at McLaren and Mercedes exactly what I'm capable of doing.

"I've said before that I came away from those tests more than satisfied with what I had achieved and boosted by the feedback I got from the test team and the technicians. I felt very comfortable in the Formula One environment and that's definitely where I want to be."