The Nashville Predators announced on Thursday that goalie Pekka Rinne, one of the teams foundational players, underwent hip surgery on Wednesday and will be sidelined for the next four months.That recovery time ought to have Rinne back and ready for the start of training camp in early September, if all goes according to plan. In 2011 and 2012, Rinne was voted as one of three finalists for the Vezina Trophy, which is voted by the 30 general managers of each NHL team for the best goaltender. This year, Rinnes production dropped off somewhat, as did that of the team.This is a situation we were aware of last year, general manager David Poile told reporters in Nashville, according to video posted on the team's website. This goes to the position hes playing, the wear and tear on the goaltenders and what the current style of play is. This is an operation that many, many players in the NHL have had.Since the invention of light, foam pads along with strong protective masks and chest protectors, goalies have adopted a style known as the butterfly, in which they drop to their knees and spread their forelegs as wide as possible to cover as much of the low part of the goal as possible. With the exception of a few older holdouts, the style has been adopted almost universally by goalies. (Prior to the advent of the lighter, more water-resistant pads, leather pads were too heavy, especially when wet, for goalies to drop down and get back up quickly; in addition, goalies did not want to risk pucks hitting them in their upper body and face, as those protectors were not as strong as those of today.)The butterfly style puts an incredible strain on the hips and it has not been uncommon for goalies in recent seasons to undergo similar procedures to the one Rinne had at Vanderbilt University Medical Center. A release described the procedure as an arthroscopy.Poile mentioned two goalies, Tim Thomas and Niklas Backstrom, who have both had the procedure. The summer after having it in 2010, Thomas went on to win the Vezina and then led Boston to the Stanley Cup in the same season. Minnesotas Backstrom, a close personal friend of Rinnes, was a co-leader in the NHL in wins this season.Poile said Rinne could have played in the playoffs if Nashville had qualified.Everybody felt with all the research that this would be the best thing for Pekka and his longevity of career and his future lifestyle, he said. It is a four-month recovery, which brings us, again, right to training camp. Its certainly our hope that he will be ready to go for training camp.Rinne just finished the first season of a seven-year, 49 million contract.