Cardiff - Dale Steyn has been diagnosed with a mild left side strain, after complaining of tightness during the Proteas’ warm-up match against Pakistan at The Oval on Monday. Steyn left the field to receive treatment after bowling five overs, and a subsequent MRI scan confirmed the injury."Dale complained of some discomfort during the warm-up match against Pakistan on Monday and because of the sensitive nature of the affected area he was subsequently taken for an MRI scan which revealed mild swelling in a left intercostal muscle, in the region of the 11th and 12th rib," explained Proteas Team Manager, Dr Mohammed Moosajee."At this stage we are unable to determine whether he will be available for the first match against India in Cardiff, however, we will be assessing and treating intensively on a daily basis."Robin Peterson suffered a hit to his left foot while batting yesterday. He experienced some swelling and was advised not to bowl during the match as a precaution, he has however responded well to treatment overnight .”Quinton de Kock has joined the squad as cover for wicket-keeper AB de Villiers. De Kock is not an official member of South Africa’s ICC Champions Trophy squad, but will travel with the squad for the tournament.Stuck in the office without a TV? If so, be sure to follow Sport24's LIVE interactive commentary on Thursday.