Tonkin has been informed that he has made the Opening Day roster, Mark Bowman of MLB.com reports.
Tonkin was added to the 40-man roster by Atlanta to protect him from the Rule 5 draft, and while he has forged a 5.87 ERA in 7.2 innings in the Grapefruit League, he's done enough to win a job to begin the season. It may be a short stint for Tonkin, however, as Bowman suggests Tonkin is likely the arm that gets sent down when Atlanta promotes Dylan Dodd for his start against the Cardinals next Tuesday.