"Playing catch up to 90 feet, feels great," general manager Alex Anthopoulos said of Santos. "So he'll obviously progress at some point here to a bullpen [session]. Right now, no setbacks at all.
"We don't have a date yet, but as long as he doesn't have any setbacks, we expect to get him back as soon as we get him into a game and maybe get him a back-to-back appearance."
Santos would have been eligible to come off the disabled list in time for Tuesday night's game against Boston, but that clearly won't happen. He has yet to appear in a game, and as a result will likely need at least another week before making his return.
That would seem longer than first anticipated, but Anthopoulos doesn't feel as though that's the case.
Santos has allowed one run on three hits in 4 1/3 innings this season. He managed to appear in just six games last year because of a right shoulder injury that eventually required surgery.
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.