Slovenian rider Kristijan Koren has been suspended for potential doping violations, the International Cycling Union has confirmed.
Compatriot Borut Bozic, Italy's Alessandro Petacchi and Croatia's Kristijan Durasek have also been provisionally suspended as part of the 'Operation Aderlass' doping inquiry.
Use of prohibited methods between 2012 and 2017 is being investigated.
Bozic is now sports director of Koren's team, Bahrain Merida.
Their alleged violations took place in 2012 and 2013, when neither was involved with their current team.
Koren is currently 65th in the Giro d'Italia standings but will not be allowed to start Wednesday's stage.
- Juan Sebastian Molano withdrawn from Giro d'Italia over 'unusual physiological results'
- Samuel Sanchez given backdated two-year ban for doping offence
A Bahrain Merida statement read: "The team strictly advocates zero-tolerance doping policy and has therefore provisionally suspended both members concerned.
"The team always carries out thorough medical checks (including biological passport check) of any new signed rider."
Austrian cyclists Georg Preidler and Stefan Denifl were provisionally suspended in March as part of 'Operation Aderlass', a week after five Nordic skiers were arrested.
The inquiry, led by Austrian authorities, is looking into blood doping, a process where athletes have blood transfusions to increase their stamina and performance, which is prohibited under World Anti-Doping Agency regulations.
A UCI statement read: "The UCI and the Cycling Anti-Doping Foundation (CADF), the independent body mandated by the UCI to define and lead the anti-doping testing strategy and investigations in our sport, have been in close contact with the sport and state authorities involved in the Aderlass investigation, in particular with Wada and the Austrian law enforcement authorities."