South Africa captain Graeme Smith has said that he believes Kevin Pietersen's decision to retire from all limited-over forms of the international game could leave a "big hole" in his life.
Pietersen announced his retirement from 50 and 20-over matches with England back in May because of scheduling issues.
The batsman has since expressed his desire to play in the World Twenty20 in September but ECB rules state that players must be available for selection in both forms of the game.
Speaking ahead of the highly-anticipated three-Test series against England, which begins at The Oval on Thursday, Smith said: "It's impossible to know what you're giving up, and how hard it will hit you, until it's gone.
"I think he'll quickly find there's a big hole in his life which isn't as easy to cope with as he may think."
England will announce their squad for the World T20, where they will defend their title in Sri Lanka, on Wednesday.
