Johnson will open the season as a member of Boston's rotation, Chad Jennings of the Boston Herald reports.
A spot was opened up for Johnson with Eduardo Rodriguez (knee), Drew Pomeranz (forearm) and Steven Wright (knee) all battling injuries. Johnson made five starts for the Red Sox last year, posting a 4.33 ERA with a 5.26 xFIP. He avoided walks (6.6 percent walk rate) but didn't strike out enough batters (17.4 percent strikeout rate) to be anything more than a back-end starter. Barring an unexpected jump in his performance level, Johnson will likely be back in the minors soon or in a long-relief role, limiting his fantasy value.