Johnson did not make the 30-man roster but will remain stretched out at the alternate training site, Bill Koch of The Providence Journal reports.
With Eduardo Rodriguez out indefinitely due to complications in his recovery from COVID-19, the Red Sox enter the season with very few established big-league starters. Johnson could join the rotation sometime soon, but the plan is for the team to use an opener as the fourth starter and one of Matt Hall or Jeffrey Springs as the fifth starter.