Andy Flower has admitted that Kevin Pietersen will need a significant rest if he is to recover from a knee injury in time for the Ashes.
England are facing a bumper-to-bumper schedule before the match-ups with Australia begin in July, and Pietersen has so far missed the third New Zealand test with the problem, which began at the start of the month during a warm-up match.
And Flower says that fans must be patient with the 32-year-old, who has also pulled out of Indian Premier League games with the Delhi Daredevils next month.
"Kevin has had a further scan and it confirms a bone injury and bone bruising that will need significant rest," Flower explained, according to BBC Sport.
"He has been put in a brace and will have to have it on for a couple of weeks. He's then got to rest for a couple of weeks and then begin his physical rehabilitation."
Greame Swan has also suffered from an elbow injury that ruled him out of action for the tests against New Zealand, which ended in a 0-0 draw, but Flower believes that the pair will both be able to come back in time for some of the year's most important match-ups, including the trip to Australia over the turn of the year.
"Swann's operation was successful and relatively simple," he said. "We are hoping he will rehabilitate his arm and his entire body ready for the challenges ahead.
"I would imagine, well hope, they'll both be fit and firing in the summer."