Financial terms weren't disclosed, but the slot value is over $6 million.
The Blue Jays selected Martin with the fifth pick in the 2020 MLB Draft in June. Many expected the Vanderbilt star to be taken second overall and some even ranked him as the best player available.
Martin offers positional flexibility after starting contests at six different positions as a freshman. He played third base later in his college career.
The 21-year-old is represented by agent Scott Boras, who had a prickly relationship with the Blue Jays before the team signed client Hyun-Jin Ryu to a four-year, $80-million contract during the offseason.