Cano is eligible to rejoin the Mariners on Aug. 14.
Dee Gordon has played second for the Mariners in Cano's absence and is batting .285 with 22 RBIs.
Seattle manager Scott Servais said Cano has been working out at third base in preparation for his return. This way, he could be more versatile when he rejoins the team. Cano will play first base and bat third Monday.
Cano would not be eligible to play in the postseason because of the suspension.
The slumping Mariners, who broke a five-game losing streak Sunday, are 2½ games behind Oakland for the second AL wild card.
Cano, an eight-time All-Star, tested positive for furosemide, a diuretic often used to mask banned substances in urine tests.
Cano had broken his wrist just before the suspension and had surgery in May.
He was hitting .287 with four homers in 169 plate appearances before the suspension.
Cano is in the fifth year of a 10-year, $240 million contract.