Mata received an invitation to the Red Sox's big-league camp Friday.
The 20-year-old will spend a few weeks with Boston's big-league coaching staff, though it might be another year before he's pushing to join the top club for good. In 11 starts at Double-A Portland last season, he posted an unimpressive 5.03 ERA, combining a strong 25.2 percent strikeout rate with a slightly high 10.3 percent walk rate.