Cape Town - The Proteas will keep a watchful eye on their most valuable player, Jacques Kallis, during the upcoming Indian Premier League (IPL).The 36-year-old had to pull out of two of South Africa's matches on their recent tour to New Zealand. At one instance he woke up with a sore back and was subsequently withdrawn for the last ODI clash in Auckland. He also missed the final Test in Wellington due to a stiff neck.There's a concern that these niggles could again flare up at any time."He could again develop a spasm and has to get constant treatment for it," Proteas team doctor Mohammed Moosajee, told Volksblad."It's due to all the wear and tear over the years. The MRI scan showed nothing suspect," said Moosajee.Moosajee said their physiotherapist, Brandon Jackson, gave the Kolkata Knight Riders' physiotherapist specific instructions on how to treat Kallis during the IPL.Kallis will play his second season with Kolkata after previously representing the Royal Challengers Bangalore.The IPL starts on Wednesday when the Chennai Super Kings take on the Mumbai Indians in Chennai.Proteas coach Gary Kirsten will hope Kallis remains injury free over the next view months, as an important tour to England awaits in July.