South Africa face an anxious wait over the fitness of experienced seamer Dale Steyn after a flare-up of an old shoulder injury ruled him out for the rest of the Indian Premier League season, putting his World Cup prospects in doubt. The 35-year-old Steyn felt discomfort having played for the Royal Challengers Bangalore on Sunday, just his second game of the competition after he was signed as an injury replacement for Australian seamer Nathan Coulter-Nile. "Upon assessment and subsequent investigations, a flare-up of his right shoulder was confirmed," South Africa team manager Mohammed Moosajee said in a statement on Thursday. "With the World Cup around the corner, it is our priority to get him back to full fitness before the squad departs on May 19. He will consult with a shoulder specialist upon his return and a recovery plan will be put in place." Steyn, arguably his country's greatest fast bowler, was sidelined from South Africa’s one-day international side for two years with shoulder, hamstring and foot problems before returning in Oct. 2018. He was last week named in a 15-man squad for the World Cup being held in England and Wales, having previously appeared at the tournament in 2011 and 2015. Steyn is viewed as a key part of a three-man pace attack that also includes Lungi Ngidi and Kagiso Rabada, this season’s leading wicket-taker in the IPL. South Africa open the World Cup campaign against England at The Oval on May 30.