American teenager Jack Sock may have a tear in his groin, and is facing the prospect of having to undergo surgery, TENNIS.com has learned. Sock, who lost his opening match at the BNP Paribas Open at Indian Wells, had an MRI while in the desert and will have a second one this week on the east coast. The first MRI did reveal what appeared to be a tear, but his regular physician wants to have another one done so he is clear as to how to proceed. If the 19-year-old does have to undergo surgery, he could be out for a few months. Sock, who is currently ranked No. 334, won the 2011 U.S. Open mixed doubles title with Melanie Oudin.