The plan is for Smith, who underwent Tommy John surgery in May 2016, to be sent to Double-A Portland on Saturday. The right-hander will throw an inning before being sent to Triple-A Pawtucket when the PawSox return from a road trip on Monday.
While the Red Sox would like to have Smith back in their bullpen as soon as possible, Farrell assured that the righty that he still has a long road ahead. The reliever hasn't pitched in a Major League game in almost 15 months.
"We're talking about a year and a half, so while there's a lot of encouraging signs, he's going to need some appearances to continue building endurance," Farrell said. "He's probably going to go through some arm strength ebbs and flows, that's fully anticipated, but this is an encouraging development."
Per a new rule in the CBA, the Red Sox can keep Smith on rehab assignment for 60 days, instead of the normal 30, since he is coming off Tommy John surgery.
• David Price threw for the second consecutive day Wednesday, moving from 60 to 90 feet. He was placed on the disabled list last week with elbow inflammation.
• Catcher Sandy Leon will not spend any time on the disabled list due to a sore right knee, and Farrell says he will be back in a starting capacity soon.
"He's been available in emergency," Farrell said. "He went through some catching -- he caught a bullpen today -- he did some blocking drills and some throwing."
Evan Chronis is a reporter for MLB.com based in Boston. This story was not subject to the approval of Major League Baseball or its clubs.