Federer & Djokovic say Wimbledon should consider rule changes after opponents retire

Roger Federer and Novak Djokovic said
Wimbledon should consider rule changes after
both their first-round opponents retired with
injuries.
Third seed Federer led 6-3 3-0 when Ukrainian
Alexandr Dolgopolov quit with an ankle injury
after 43 minutes.
Second seed Djokovic progressed after a calf
injury saw Martin Klizan pull out at 6-2 2-0 down
on 40 minutes.
"We had a joke in the locker room saying we
should maybe play a practice set on Centre
Court," said Djokovic.