NESN’s Jenny Dell and Tom Caron joined Red Sox Foundation executives at the New Balance store in Copley on Wednesday to announce that the next New Balance-sponsored “Run-Walk to Home Base” event will be held on May 4, 2013. The annual activity, which Dell and Caron participated in this year, raises money for Home Base, a Mass General program that provides clinical care for Iraq and Afghanistan veterans affected by combat stress and traumatic brain injury. Not surprisingly, the finish line for the walk-run is home plate at Fenway Park.