Dutch team LottoNL-Jumbo have sent three of their riders home for possessing sleep medication not sanctioned by the team.

The product, not identified in the team’s release on Wednesday night, is not a banned substance, but was being used by the riders without it being provided or used by the team. LottoNL described it as a ‘serious violation’ of their strict regulations.

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The three riders, Juan José Lobato, Antwan Tolhoek and Pascal Eenkhoorn, were sent home from a team training camp in Girona, Spain. The team said they then had a collective meeting with riders and staff over the issue.

“Because of their unacceptable behaviour, the team’s management has expelled the three riders indefinitely,” the statement said.

“At a meeting with all riders and staff present earlier this evening, the entire team strongly distanced themselves from this behaviour, which contravenes the core values of the team. The three riders involved were also present. Where necessary, they shall be guided to prevent recurrence.”

28-year-old Spaniard Lobato, formerly of Movistar, joined the team for 2017 and is in his last contracted year with the team, as is 23-year-old Dutchman Antwan Tolhoek. 20-year-old Belgian Pascal Eenkhoorn, a neo-pro, is only just about to join the team for is first year in the WorldTour.

LottoNL’s Girona training camp ends on Friday, with the team preparing to make their season debut at 2018’s first WorldTour race, the Tour Down Under.