World champion Sebastian Vettel believes that Michael Schumacher's decision to retire from Formula 1 will prove to be a "big loss" to the sport.

The seven-time champion announced that he will call time on his racing career at the end of the season after Mercedes confirmed that Lewis Hamilton will replace the German for the next campaign.

"It's a big loss," said Vettel. "It's a shame. There are a lot of people who would have loved him to continue, including myself. I hope he stays around in some other function so at least we get to see him from time to time."

Meanwhile, Hamilton has insisted that opting to leave Mercedes was one of the "most difficult" decisions that he has had to make in his career.