Czech Republic driver Josef Kral has lost his race seat at Barwa Addax for this forthcoming weekend's GP2 round at Monza, despite his success last weekend at Spa-Francorchamps.

Kral had admittedly been having a lacklustre season of it in 2012 scoring minimal points and even being replaced for two race weekends in Bahrain earlier in the year in favour of the more experienced Dani Clos.

But he had a breakthrough weekend when he followed up a fourth place in the feature race with a spectacular launch from the grid at the start of the Spa race to take the lead going into La Source which he then held through to the chequered flag for his maiden GP2 Series victory.

However, it's been reported that despite that success, Kral will not appear for the team again at Monza this weekend and will be replaced instead by the London-born American driver Jake Rosenzweig, who competed with the team at last year's one-off GP2 Final race in November.

The news came from the GP2 Media Service, with the series' website registering the change on its driver listings for the forthcoming weekend and the site's Twitter feed confirming th news on Thursday morning. There was nothing immediately available directly from the team or the drivers concerned.

No explanation for the substitution was given, and it appears that the decision might have been made before Kral's unexpected success at Spa. Rosenzweig himself has not been having the most successful of seasons, and is currently in 20th position in the Formula Renault 3.5 with just 8pts after six out of nine rounds.

Barwa Addax is the third team to announce changes to their driver line-up for Monza following the weekend at Spa.

Coloni announced on Tuesday that they were splitting with Stefano Coletti in what was referred to as a "separation by mutual consent," and on Wednesday announced that they were bringing back last year's runner-up in the drivers' championship Luca Filippi to race for them in Italy.

Coletti then announced that he would be driving for Rapax at Monza, in the car previously driven in 2012 by Tom Dillmann and more recently Dani?l de Jong.

"I am very happy for this new agreement that will allow me to race in Monza with Rapax," said the 23-year-old Monegasque driver after the news was confirmed. "I already had the chance to do some testing with them in the past and in that occasion I found a top class technical and human structure.

"Monza is also a home race to me as I live 300 kilometres from the circuit, I am well motivated to do good things there," he said, adding that he wanted to "thank Team Rapax managers for showing interest and high esteem for me in several occasions."

Monza is the penultimate round of the 2012 GP2 Season, with the final weekend of the year coming later in September at Singapore. It's not known whether any of the three driver deals announced in the last 48 hours - Filippi, Coletti or Rosenzweig - will extend to the season finale or are Monza-only arrangements.