 He later obtained his Bachelor's degree at Mercy College in Dobbs Ferry, New York.Jefferson displayed impressive speed and agility and was selected by the New York Mets organization in the first round (20th pick overall) of the free agent draft on June 6, 1983.After playing in the minors for three years, Jefferson played in 14 games for the Mets during the last month of the 1986 season before he was sent to the San Diego Padres in the nine-player Kevin McReynolds-Kevin Mitchell deal at the end of the year.