[2] While riding for Blanco Pro Cycling in 2013,[6] Slagter won the Tour Down Under, his greatest career achievement.

He was joined by three riders on the descent, and with the peloton on their heels, Slagter out-sprinted the group.

[7] On the fifth stage, he gained the orange jersey; finishing atop Old Willunga Hill in second position, behind Australian Simon Gerrans (Orica–GreenEDGE), the defending champion.

Slagter rode the Tour de France, and finished 9th on stage 16 to Bagneres-de-Luchon.

After one season with B&B Hotels–Vital Concept, Slagter announced his retirement in November 2020; he intended to become a tractor salesman.