Rob Gronkowski appears to have dodged one bullet. The nasty infection that’s dogged him for months looks to be a thing of the past, as doctors yesterday were able to install a new plate in his surgically repaired left forearm. But there’s another sizable worry on the table. The Pro Bowl tight end will likely tackle back surgery next. Gronkowski has been battling a disc problem for at least the past year. He recently underwent an MRI to determine the extent of the injury. According to a source with knowledge of the situation, the surgery avenue will be explored in a month’s time as doctors will decide if a piece of the troublesome disc needs to be removed. If that’s the case, the surgery is expected to be performed by Dr. Robert Watkins, who operated on Gronkowski in 2009 for the initial back problem that dropped the tight end’s draft stock. At that time, when Gronk was at the University of Arizona, Watkins performed a microscopic lumbar discectomy. Until now, Gronk hadn’t had any issues with the back since that surgery. One source told the Herald the Pats medical staff had to work extremely hard on a weekly basis to keep the tight end on the field because of the back problem. Watkins is once again expected to evaluate Gronkowski at his California facility next month, and determine if the surgery is needed at that time. Should Gronk undergo that surgery, which is a fairly high probability, the combined recovery time along with down time and rehab from the plate replacement is roughly four months, assuming there are no setbacks.