Saunders (shoulder inflammation) and Smoak (quad strain) both went on the 15-day disabled list Wednesday, though Smoak's was retroactive to June 10, which means he'll be eligible to return to the Mariners on June 24.
Hart sustained a hamstring strain May 18 in Minnesota and subsequently landed on the 15-day disabled list. He began running and taking batting practice during the Mariners' latest homestand, but will probably require the longest rehab stint of the three.
Hart was hitting just .209 with five home runs and 17 RBIs in 37 games after missing all of 2013 because of microfracture surgeries on both knees.
"Obviously, I think Saunders and Smoak will come quicker because they have been playing," McClendon said. "We have to be careful with Corey and make sure we build his at-bats up and he's swinging well and he's running well. They both got to pass the test. Smoak and Corey and Saundo's gotta pass the test swinging the bat before they go out."
Smoak has a .208/.282/.361 slash line with seven homers and 29 RBIs in 63 games. Saunders is faring better, hitting .272 with four homers and 25 RBIs. All could help an offense that entered Sunday ranked 12th in the American League in runs scored.
Adam Lewis is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.