Clint Frazier discovered the supposed restorative powers of hydration on Wednesday. When he arrived at Steinbrenner Field, he felt foggy, his head throbbed and his appetite had disappeared — telltale symptoms of the concussion he had been diagnosed with after twice colliding with the wall in an exhibition game Saturday. Then, on the advice of Russell Wilson, the Seattle Seahawks quarterback who is in camp this week with the Yankees, Frazier began drinking water — and lots of it. Frazier guzzled six 12-ounce bottles over an hour or so Wednesday morning, and suddenly the symptoms diminished. His headache dissipated and his hunger returned. “I don’t know for sure,” Frazier said with a laugh, estimating that he had drank a gallon of water. “But it pumps oxygen to your brain a lot, so I feel alive right now. Maybe I was lacking water; I don’t know. Maybe I just feel good.” The handling of Frazier’s brain injury is another example of how despite a raised awareness of concussions — and detailed protocols for diagnosing them — the treatment of such injuries remains murky in sports, where there are many interests competing with a player’s welfare. Continue reading the main story Wilson himself has experience with the issue. During a game in December, he ducked in and out of a treatment tent in a matter of seconds after he was sent there for a concussion evaluation. The Seahawks were hit with a $100,000 fine for evading the protocol. Wilson was also criticized in 2015 for suggesting that a brand of fortified water, in which he had invested, had helped to prevent a concussion during a playoff game. While baseball is not the contact sport that football is, the Yankees still are no strangers to head injuries. Catcher Austin Romine was sidelined with a concussion in 2013, as was infielder Stephen Drew in 2015. And last season, Jacoby Ellsbury missed a month with a concussion after crashing into the center-field wall at Yankee Stadium to make a catch. Ellsbury was allowed to remain in the game to finish the inning. Frazier’s first collision Saturday came when he made a leaping catch in the first inning before falling and hitting the back of his head on the outfield wall. But his injury may have been the result of a second, lesser collision he had with the wall several innings later. His head did not hit the wall, but his shoulder did, leaving Frazier to wonder if the second collision was jarring enough to exacerbate the first. Frazier was not evaluated on the field, but was checked out when he returned to the dugout at the end of the first inning. “I made it through the game and felt fine,” Frazier said. “That’s why it was frightening afterward. That’s why you have to take it seriously.” Still, Frazier admitted to feeling conflicted. He arrived to spring training determined to play his way onto the opening day roster, a tall task but one that is not out of reach for a former No. 4 overall draft pick. He can’t earn a spot unless he’s on the field.