Team Sky rider Ben Swift spent the night in intensive care in Tenerife following a crash while out training with Tour de France winner Geraint Thomas.
Swift's team said he clipped a rock on a descent, causing bleeding from the spleen which required immediate treatment.
The 31-year-old Yorkshireman also suffered multiple contusions and facial injuries, but no apparent fractures.
Late on Thursday, Swift wrote on Twitter: "Thanks for the well wishes. I am still in intensive care at the moment. But hopefully move onto a normal ward tomorrow.
"They have stopped the bleed in the spleen. But just need to keep monitoring it. Along with that I have facial wounds and road rash."
Team Sky doctor Inigo Sarriegu said in a statement: "Swifty suffered quite a heavy crash whilst out training.
"Thankfully though, he didn't lose consciousness and was aware of the incident afterwards.
"We will continue to monitor him over the coming days, but 24 hours on from the crash he is already feeling better."
Swift, who finished second in Milan-Sanremo in 2016 and fifth in the 2017 UCI Road World Championships, rejoined Team Sky this winter on a one-year deal after two seasons with UAE Team Emirates. He previously raced for the British squad from 2010 to 2016.
Ben Swift will return to Team Sky in 2019, the British WorldTour team have announced.
The Rotherham-born rider joined Sky for their launch in 2010 but has spent the last two seasons with UAE Team Emirates after leaving in 2016.
The 30-year-old said he was excited to be returning to a place where he knows he can fit straight back in.
"It's a great feeling to be re-joining Team Sky," Swift said.
"Obviously I know the ins and outs of the team. I feel really comfortable here and it's a place I've grown as a rider."
Most of Swift's best results, including podium finishes at Milan-San Remo in 2014 and 2016 - came in Team Sky colours.
His time with the UAE Emirates squad was frustrated by injuries, though he managed fifth place in last year's road world championships in Bergen, Norway racing for Great Britain.
He will now return to Sky as an experienced head, and the team's performance manager Rod Ellingworth said they would look to him to mentor their younger riders.
"Ben has got a crucial role to play next season," Ellingworth said. "He's not only a fine rider in his own right, but he's also a superb role model for the younger riders on the team to learn from, as we look to bring through the next generation at Team Sky."