Strikeout ace Johnson pitched for San Francisco, Wells for Cincinnati and Grabow for Pittsburgh and the Chicago Cubs in 2009.
Johnson has pitched 22 seasons in the major leagues for the Montreal Expos, Seattle Mariners, Houston Astros, Arizona Diamondbacks, New York Yankees and San Francisco, compiling a record of 303-166 with 4,875 strikeouts. He was 8-6 with the Giants in 2009.
Wells, who has also pitched for the Washington Nationals, was 2-5 last season with the Reds.
Grabow was 3-0 in 75 relief appearances in 2009.