He played in Major League Baseball (MLB) for the Seattle Mariners, Pittsburgh Pirates, Boston Red Sox, and New York Yankees.

He was also named first-team all-district and was an honorable mention selection as a pitcher and helped lead Clay to a league championship.

The lefty starter helped the Penguins capture a Horizon League Title in the 2004, pitching the team into the finals and making their first ever appearance in the College World Series.

He left Youngstown State ranked second in strikeouts with 250 and is the only pitcher in school history to pitch back-to-back seasons of at least seven wins.

After signing with Seattle in June of that year, Thomas made his professional debut for the Everett AquaSox of the short-season A affiliated Northwest League.

In 2007, Thomas was promoted to Double-A West Tenn Diamond Jaxx, but began the season on the disabled list with a strained left elbow.

Upon being activated from the DL, Thomas struggled with control problems, posting a 4-9 record with a 5.51 ERA and a career high 61 walks.

On April 4, 2012, the Red Sox selected Thomas' contract, adding him to their major league roster for their regular-season opener against the Detroit Tigers the following day.

On November 21, 2012, Thomas signed a minor league deal with the Oakland Athletics that included an invitation to spring training.