Toro, who is batting .179 with six homers and 13 RBI, was injured in Saturday’s loss when he collided with right fielder Adam Frazier going after a pop-up in the first inning, hitting the ground after a catch.
The 33-year-old Souza appeared in just six games, going 3 for 19.
To take their place, they recalled outfielder Taylor Trammell and selected utility player Sam Haggerty from Triple-A Tacoma.
Seattle enters Sunday having lost 18 of its last 24 games and has dropped the first three of a four-game series against the Red Sox.
Mariners host Baltimore Orioles, look to end home losing streak
Baltimore Orioles (35-40, fifth in the AL East) vs. Seattle Mariners (34-41, fourth in the AL West)
Smith leads Diamondbacks against the Padres following 4-hit game
San Diego Padres (45-30, second in the NL West) vs. Arizona Diamondbacks (33-41, fourth in the NL West)
Pirates come into matchup against the Nationals on losing streak
Pittsburgh Pirates (29-44, third in the NL Central) vs. Washington Nationals (28-48, fifth in the NL East)
Guardians host the Twins on 4-game home skid
Minnesota Twins (42-33, first in the AL Central) vs. Cleveland Guardians (36-33, second in the AL Central)
Yankees bring 1-0 series advantage over Athletics into game 2
Oakland Athletics (25-50, fifth in the AL West) vs. New York Yankees (54-20, first in the AL East)
Phillies play the Braves after Castellanos' 4-hit game
Atlanta Braves (42-32, second in the NL East) vs. Philadelphia Phillies (39-35, third in the NL East)