The Red Sox have had their share of injuries this season, but one body part in particular is getting more than its fair share of hurt. The head. David Ross is the second Red Sox player this season to go on the disabled list with a concussion. And, it was learned yesterday, just like Stephen Drew earlier this year, Ross will be sidelined longer than originally expected. Rather than join the club here for the end of this series, the Red Sox catcher was not well enough yesterday to be examined by a concussion specialist. That exam was pushed back to Monday. Ross might be feeling better by Monday. However, the fact he still was experiencing concussion symptoms six days after taking two hard foul tips off the front of his catcher’s mask (May 11 at Fenway Park) means there is absolutely no telling how long he will be out. “Everything pointed to him being re-examined there and him joining us here in Minnesota, but much like we’ve seen with many other concussions, these things take on a life of their own,” Red Sox manager John Farrell said before last night’s game. “He’s still experiencing some light-headedness and fatigue, so we’ve just got to give it time.” When Drew was hit on the front of his batting helmet by a pitch on March 7 during a Grapefruit League game against the Twins in Fort Myers, he did not leave the game right away. The Red Sox planned to have him back in the lineup the following day, but the night of the beaning, Drew began to experience dizziness while reading, and that was the beginning of a stint on a seven-day disabled list that turned into more than a month out of action. He visited a concussion specialist in Pittsburgh before finally being activated on April 10.