The plan is for Bailey to again face teammates on Saturday, and then start a Minor League rehab assignment.
"Everything went great," said Bailey. "I threw 20 pitches. Everything felt good -- fastball, cutter, curveball, changeup. It went well."
Bailey estimates he would need five to six Minor League outings before being ready to join the Red Sox.
Conceivably, he could be pitching for Boston by mid-August if there are no setbacks.
When the Red Sox traded Josh Reddick to the Oakland Athletics for Bailey in December, they envisioned he would be their closer. But that plan never took shape, thanks to Bailey being forced to undergo right thumb surgery the day before the regular season started.
"It was nice to see hitters in the box," Bailey said. "I'm just anxious to get back out there and help this team win. The thumb feels great, the forearm feels great. Now it's just a matter of getting back with hitters in the box in game situations. Hopefully soon, I'll be back with the team."