The following was issued by WWE on Sunday morning:
"WWE.com has learned that WWE Champion John Cena sustained an injury during WWE's European tour. The WWE Champion injured his right Achilles tendon while battling Ryback.
The injury raises questions about the scheduled match between Cena and Ryback at Extreme Rules on May 19. What lies ahead for the Cenation leader? Does this put Ryback one step closer to capturing the WWE Title?
There are no details yet about Cena's expected recovery time.
For more, stay with WWE.com and tune in to Monday’s Raw at 8/7 CT on USA Network."