On Monday, Chris Cotillo of MassLive.com reported the American League East team released Johnson after he requested an exit.
"Johnson felt like he wanted an opportunity," manager Ron Roenicke said. "Sometimes you need to go other places to get that."
Cotillo previously reported Johnson was not opting out of the season amid the COVID-19 pandemic but seemed on his way out of the Red Sox organization.
Cotillo noted Johnson was not on the Red Sox's 40-man roster and had been pitching at the team's alternate training site in Pawtucket, underscoring how far away he was from the major league level.
It's not as if Boston is loaded with elite pitchers either with Chris Sale and Eduardo Rodriguez out for the season, but Johnson was never able to separate himself from a group that included Nathan Eovaldi, Martin Perez, Ryan Weber, Matt Hall, Chris Mazza, Zack Godley and Dylan Covey.
Johnson, who was a first-round pick, has been inside the Red Sox organization for eight years.
He has 65 career appearances at the major league level with 38 coming in 2018 and 21 coming last year.
He has a career ERA of 4.74 to go with a 1.55 WHIP, and his best season came in 2018 when he pitched 99.1 innings with a 4.17 ERA, 1.43 WHIP and 87 strikeouts for the eventual World Series champions.