Yet another concert has been added to the already crowded summer calendar at Fenway Park. Country singer Jason Aldean will be at the ballpark Sept. 9 with co-headliner (and Bill Belichick buddy) Kid Rock. Aldean played two shows at Fenway in 2013. Previously announced shows at Fenway this summer include the Zac Brown Band, who’ll set up in center field Aug. 20 and 21; the Dead & Company — featuring former Grateful Dead members Bob Weir, Mickey Hart, and Bill Kreutzman with John Mayer, Allman Brothers’ bassist Oteil Burbridge, and RatDog keyboardist Jeff Chimenti — July 15 and 16; Eddie Vedder and Pearl Jam Aug. 5 and 7; James Taylor and Jackson Browne Aug. 3; and Piano Man Billy Joel Aug 18.