 Kallio suffered a serious knee injury when racing as a scheduled wildcard entry at the Sachsenring, Germany round in July 2018, disrupting the KTM test programme, causing the factory to contract Randy De Puniet as a replacement test rider for the remainder of 2018, and to end any future test-rider entries as presenting an unacceptable risk to their plans.KTM MotoGP rider Pol Espargaro was also injured soon after.In 2019 he replaced Johan Zarco mid-season after Zarco broke contract.