Winner of the Italian Grand Tour in 2000 and last year's classification winner, Garzelli slammed the UCI for its decision to overlook his team in favour of four others - Farnese Vini-Selle Italia, Colnago-CSF Inox, Androni Giocattoli and Team NetApp.
"I am saddened and disappointed by this news," Garzelli wrote on his personal website, "and at this point I am seriously considering the idea of ending my career here.
"When the money has the upper hand over sporting merit, and over someone who has been a protagonist for 15 years of joys, sweat and suffering, putting on a show for the fans, but also for the organizers, and none of this is taken into account - it means that it's time to stop neglecting my family.
"In a month my wife will make me a father for the fourth time and without important goals to be achieved, where can I find the motivation to train, go to camp and spend time away from them when, in the end, you find yourself without the possibility of trying to achieve those results for which you have made so many sacrifices?"
Garzelli said he had planned to contest one final Giro before hanging up his boots.
"I have known that for a few years I haven't been competitive in the general classification, but in recent editions I have always made a mark, winning an important stage as in 2010 or winning the two green jerseys in 2009 and 2011," he said.
"This has made me incredibly happy and proud because I think I've exceeded all expectations."