He played in Major League Baseball (MLB) from 2004 through 2009, with the Boston Red Sox, Oakland Athletics, and Kansas City Royals.

The Boston Red Sox selected DiNardo in the 10th round of the 1998 Major League Baseball draft, but he did not sign, opting to attend Stetson University instead.

[2] As is the requirement with Rule 5 selections, DiNardo would remain on the Red Sox major league roster during the entire 2004 season.

With the 2004 Boston Red Sox, DiNardo made 22 appearances (all in relief) compiling a 4.23 ERA in 27+2⁄3 innings pitched; he did not register a win or a loss.

For the 2005 Boston Red Sox, DiNardo appeared in eight games (one start), compiling an 0–1 record with 1.84 ERA in 14+2⁄3 innings pitched.

For the 2009 Kansas City Royals, DiNardo appeared in five games (all starts), compiling an 0–3 record with 10.12 ERA in 21+1⁄3 innings pitched.

On January 8, 2010, DiNardo signed a minor league contract to return to the Oakland Athletics; the deal included an invite to spring training.

[8] He played in the rookie-level Arizona League and for the Triple-A Sacramento River Cats, making 12 appearances (11 starts) with a 3.53 ERA and 2–5 record.

On April 14, 2011, DiNardo signed with the Long Island Ducks of the independent Atlantic League of Professional Baseball.

[13] DiNardo plays guitar and has been a part of the annual Hot Stove Cool Music concert in Boston.