Sometimes it's possible to catch a rising musician at the very start of his career before he becomes better known to the general listening public. Such is the case with jazz pianist Aaron Diehl. Diehl is already making a name for himself in New York in joint concerts with the likes of Wynton Marsalis, Eric Reed, Marcus Roberts, Wess Anderson and Jonathan Batiste at various clubs, at The National Jazz Museum in Harlem and at Jazz at Lincoln Center. Ironically, Diehl's first CD was pro …