Lem was drafted in 1984 by the Baltimore Orioles as a catcher and first baseman. In 1986, the Boston Red Sox drafted Lem out of Columbia State Community College.

He played in the Red Sox, Blue Jays and Mariners organizations and was a 2-time minor league all-star. Lem also coached with the Mariners organization for 2 years. He started giving lessons in 1986 and opened Hit After Hit in November of 1993.