With Tonio Liuzzi enjoying his third Grand Prix for Red Bull this weekend, his current run is due to come to an end.

Teammate Christian Klien partnered David Coulthard in the first three races of the 2005 season, before handing over to Liuzzi for the San Marino, Spanish and Monaco events.

Talking to reporters in Monaco, team boss Christian Horner said that it is not decided whether Klien will drive the second car at the Nurburgring or whether Liuzzi will continue as Coulthard's partner. However, a decision will be made on Monday.

"After Sunday we will take a decision as to who sits in the car for the next batch of races," said Horner. "We'll have those facts by Sunday evening.

"Christian did very well in his three races before Tonio came in so we have a very healthy situation, with healthy competition," he continued. "He is chomping at the bit to get back in the car."

Referring to Liuzzi, who made his F1 debut last month, the Englishman said: "We are pleased with the job that he's done. "He had a very good debut race in Imola, when the car wasn't comparatively performing as well as it had done previously.

"For a debut race he drove very strongly and ultimately got a point out of it," he added. "In Barcelona he had a lot of fuel in the car and made a mistake. Hopefully he will have learnt from that.

"I think for a rookie he's done an excellent job so far."

When Klien made way for Liuzzi, the Austrian's future looked uncertain as the rules stated that the driver of the third car on Grand Prix Fridays should not have taken part in more than 6 events in the previous two seasons - this would have meant bringing in another driver.

However, the FIA and the other nine teams opted to waive the rule and allow Klien, who drove for Jaguar in 2004, to continue.