Aaron Michael Heilman (born November 12, 1978) is an American professional baseball player and pitcher for the Arizona Diamondbacks in Major League Baseball (MLB). Heilman was drafted by the New York Mets out of Notre Dame in 2001. He came up through the Mets system as a starting pitcher but was converted to a relief pitcher in 2005. After the 2008 season, Heilman was traded to the Seattle Mariners, but was traded a month later to the Chicago Cubs.

High school years

Heilman was born in Logansport, Indiana and attended Logansport High School, where he was a letterman in baseball. He led his team to two regional titles, and as a senior, was a team M.V.P. and an All-State selection. Heilman graduated from Logansport High School in 1997.

College career

After a successful college career at the University of Notre Dame, he was selected by the New York Mets in the first round of the 2001 amateur draft with the 18th overall pick. Heilman was a management information systems and philosophy major in the Mendoza College of Business at the University of Notre Dame.

Major League Baseball career

New York Mets

Heilman made his major league debut at Shea Stadium on June 26, 2003 in a 6-1 loss to the Florida Marlins. He has pitched poorly as a starting pitcher, posting an ERA of 5.93 as a starter for 2003, 2004 and the beginning of 2005. Heilman's finest game came as a starter on April 15, 2005, when he made a start in place of the injured Kris Benson and pitched a one-hit complete game shutout. However, he was converted to a relief pitcher for the rest of 2005 and excelled with an ERA of only 2.18. In the second half of the 2005 season, he held a 0.68 ERA, leading the league.

In Game 7 of the 2006 NLCS, Heilman surrendered a tie breaking, two-run home run in the top of the ninth inning to Yadier Molina of the St. Louis Cardinals, putting St. Louis ahead 3-1. St. Louis would hold on to the lead to win the National League pennant, while Heilman suffered the loss for the Mets.

Chicago Cubs

After a dismal 2008 season, Heilman was traded to the Seattle Mariners in a three team trade for J.J. Putz.
However, on January 28, 2009, the Mariners traded him to the Chicago Cubs for Ronny Cedeño and Garrett Olson.

Arizona Diamondbacks

On November 19, 2009 Heilman was acquired by the Diamondbacks, in return for Scott Maine and Ryne White.