"I count on Rafa for everything, he can play singles and also in doubles," Spanish captain David Ferrer said.
"The calendar is so tight, a lot of tournaments, no days off or not as much days off as I want," Wimbledon winner said.
Injury prompts 2022 Wimbledon winner to pull the plug on Asian swing.
The 27-year-old Sramkova won her first WTA title a week after falling in the Monastir final.
Japanese qualifier will face Marin Cilic in the quarterfinals.
Iga Swiatek won't be defending her China Open crown.
TC's Laver Cup coverage starts on Friday at 7 a.m. Eastern time.
