This is likely a 1947 Pittsburgh Pirates team ball, as all players were with the franchise that year and '47 was Howell's only year. Wagner served as a coach, and is typically found on Pirates team-signed balls of the era. His signature would be the main determining factor of value, but the overall value is hurt by the fact it's an "American League" ball versus National (Pirates are an NL team) as well as the small number of signatures on it. Even so, depending on the clarity, placement and size of the Wagner autograph, your ball is worth at least $200, but as much as $400, again relative to the specifics of Wagner's signature.
Harry Howell - baseball - was born on 1876-11-14.
Jack Howell - baseball - was born on 1961-08-18.
Pat Howell - baseball - was born on 1968-08-31.
Harry Howell - baseball - died on 1956-05-22.
John Howell - American football - was born on 1978-04-28.
Bill Howell - American football - was born on 1905-04-21.
Bill Howell - American football - died on 1981-08-23.
Harry Howell was born November 14, 1876, in NJ, USA.
Dixie Howell died March 18, 1960, in Hollywood, FL, USA.
Harry Howell died May 22, 1956, in Spokane, WA, USA.
Dixie Howell was born January 7, 1920, in Harold, KY, USA.
Jay Howell was born November 26, 1955, in Miami, FL, USA.