The Giro d'Italia lost one of its top contenders on Tuesday as Colombian climber Miguel Angel Lopez of Astana pulled up with the peloton headed towards a Mount Etna summit finish on stage 4.
Lopez finished third on both the Vuelta a Espana and the Giro in 2018 and has stage wins on all three grand tours, and the 28-year-old's loss somewhat isolates team leader Vincenzo Nibali.
Sicilian native Nibali is in the spotlight Tuesday with an attack on the 23km climb up Mount Etna expected from the veteran on what could be his final Giro.
Lopez has had poor luck in Sicily as the last time the Giro came here in 2020 he hit a pothole and was propelled into a building during the Palermo time-trial.
Earlier in the race a motorbike caused several riders to tumble when it clipped a road island sending the rider sprawling to the floor.
The 21-stage Giro started with three stages in Hungary, with Tuesday's race the first Italian instalment of the 3445km marathon that ends in Verona May 29.