"He's in the early phases of his throwing program and really nothing more than that," Farrell said before Friday's game in Kansas City.
McGowan is currently out with plantar fasciitis in his right foot. Farrell said the right-hander isn't going to be back soon.
"Everyone's going to ask 'what's the projected timeline,'" Farrell said. "We almost look at it as timelines within each phase. Flat ground phase, bullpen phase and then ultimately games. Just in that description, there's still some time that's going to be needed for Dustin."
In more injured-pitcher news, Brett Cecil experienced a groin injury in a Double-A game for New Hampshire on Thursday night. Farrell said he wasn't sure how many starts Cecil will miss.
"To be determined," Farrell said. "He felt a little bit of a popping or a grabbing sensation in the left groin, and he was examined today. I think the projection right now might be two starts, but it's going to be determined on how quickly he responds, probably in the next three to five days, on what time he'll miss."