McCullers spoke with reporters Saturday, one day after undergoing the MRI. The hard-throwing right-hander said he still has soreness in his pitching shoulder and that he will approach his recovery on a day-by-day basis.
"The MRI came back 100 percent clean," McCullers said. "I'm fine."
McCullers, who is expected to have an important role in Houston's starting rotation, said he is not worried about missing the start of the season but conceded that he might not be available in early April.
"I can't really worry about [missing the start of the season]," he said. "I want to start the season obviously with the club. That's my 100 percent goal right now.
"But like I've discussed, 150 games are more important than those first two, if it comes to that."
McCullers, 22, made 22 starts as a rookie last season, going 6-7 with a 3.22 ERA and 129 strikeouts over 125⅔ innings.