The Australian, who won two stages at the first of three Grand Tours he's taking part in this season, pulled out of the race midway through the stage from Foggia to Guardia Sanframondi in southern Italy. His team later confirmed that he had been suffering from knee pain.
On Monday, Ewan took to Twitter to confirm his injury and thank people for sending messages of support after his departure from the race.
"Thanks to all the people sending nice 'get well soon' messages," Ewan wrote. "I've done some stuff with my positioning to help the knee pain I've felt since the start of stage 8. Once it's completely gone, I'll resume my training to prepare for the Tour.
"Honestly, it'll be hard to watch the sprint today at the Giro d'Italia and also on the 13th stage as I felt my form was coming to its best."
Ewan was wearing the maglia ciclamino as leader of the points classification when he withdrew from the race, having won in Cattolica on stage 5 and the uphill sprint to Termoli on stage 7 in stunning fashion.
He also had a message for those who have said that he disrespected the race by leaving early.
"To the people who think I've disrespected the race, I'm sorry you feel that way. If you saw the hard work and dedication I've put into my preparation to honour this race and perform at my best, I'm sure you wouldn't think the same. I'm more disappointed than anyone."
Ewan said before the Giro d'Italia that winning a stage at each Grand Tour was his goal for the 2021 season, adding that he'd evaluate his preparations for the Tour de France upon winning a stage in Italy.
Earlier on Monday, Ewan came under fire from Eddy Merckx in a column for Het Nieuwsblad on Monday. Merckx wrote that Ewan's actions were unprofessional.
"That Caleb Ewan also bothers me enormously. I find his statement a total lack of professionalism and lack of respect for the Giro and the sport of cycling. He deserves a sanction: take away all the bonuses. Former Tour boss Félix Lévitan would have said: 'you won't be at this race next year'."
Merckx's son, ex-pro Axel, also chimed in, accusing Ewan of leaving the race without showing any proof of his injury.
"Rules are rules – you can't take away bonuses. But to just leave, without any real proof of knee pain, that's a total lack of respect towards the organisation."
Just a short message on my departure from the giro pic.twitter.com/AwSR8AAN01May 17, 2021
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