De La Rosa (elbow) underwent a second injection of stem-cell therapy this December and is not expected to be ready for Opening Day, Nick Piecoro of the Arizona Republic reports.
General manager Mike Hazen says the second injection was precautionary as De La Rosa attempts to avoid a second Tommy John surgery. The tentative plan is to ease the 22-year-old back as a reliever. De La Rosa is coming off an injury-plagued 2016 season, in which he posted a 4.26 ERA, 1.24 WHIP and 54:20 K:BB in 50.2 innings.