Rigoberto Uran rides with his teammates of the US's Cannondale Drapac cycling team during the 165km 16th stage of the Tour de France

Cannondale-Drapac on Thursday told riders and staff that the US WorldTour team will enforce its 2018 contracts, according to an email leaked to VeloNews.

"As of right now, I am informing you that if you have a contract with Slipstream Sports for 2018, we are enforcing your contract. More to come," Vaughters said in the email, according to VeloNews.

Cyclingnews independently verified from multiple sources that riders had indeed been sent this message.

The team announced late last month that it was in limbo following the withdrawal of an expected sponsorship partner for 2018, eventually starting a crowd-funding campaign to help fill a $7 million shortfall. As of Thursday, that effort had reached $522,850 from 4,269 donors.

Tour de France runner-up Rigoberto Uran said he would give Vaughters two weeks to sort out a sponsor before deciding if he would switch teams. That was 10 days ago, but the Colombian refused to comment when reached by Cyclingnews in Quebec earlier today, saying he knew nothing yet.

Sep Vanmarcke is under contract for 2018, but told Het Nieuwsblad he couldn't afford to wait for the team to find a sponsor.

Other riders under contract through next season include Brendon Canty, Hugh Carthy, Joe Dombrowski, Sebastian Langeveld, Taylor Phinney, Pierre Rolland, Tom Van Asbroeck, and Dylan van Baarle.

Slipstream's crowdfunding campaign with Indiegogo had a 'flexible goal' of two million dollars, with the Fairly Group 'and other generous supporters' apparently matching all donations up to the goal. Indiegogo projects with flexible goals receive all funds raised, even if they do not reach the full goal amount.

In making the initial announcement, Slipstream Sports, the management company that owns the team, said an expected sponsor had fallen through.

"On Saturday morning, Slipstream Sports notified all riders and staff of the uncertainty of our organisation's future," the initial statement read. "Yesterday management received some discouraging news about a new partner we anticipated joining us in 2018. Without this partner's support, we cannot guarantee our financial security and subsequently our UCI WorldTour license for 2017."