Stefano Coletti has left Scuderia Coloni on the eve of the penultimate GP2 round of the season at Monza.
The Italian outfit announced on Tuesday that the Monegasque racer, who sits 14th in the championship, has left the team following last weekend's races at Spa.
A statement from Coloni said: "The Belgian round of GP2 in Spa-Francorchamps was the last one together for Scuderia Coloni and Stefano Coletti.
"As the objectives that had been set at the start of the season were not met, the team and the driver agreed to part ways."
Coletti switched to Coloni from Trident for his second full-season of GP2, hoping to build on the form the team showed in the second half of 2011 which took veteran Luca Filippi to second in the championship behind Romain Grosjean.
However, the 23-year-old, who won twice for Trident last year on his way to 11th in the standings, has only one podium finish to his name in 2012, and has only scored points seven times in 20 races.
The team has also endured a difficult campaign, which culminated in the announcement earlier this year that it will leave GP2 at the end of 2012, due to what the series organisers described as "a disagreement between Coloni Motorsport and GP2 Organisation."
Coloni added that a replacement for Coletti "will be announced in the next few days", as the team prepares for its home race this weekend at Monza.