Severino is scheduled to make his MLB debut on Wednesday against the Boston Red Sox at Yankee Stadium.
The Yankees did not make a trade for a pitcher before the league's July 31 deadline, and on Thursday the team placed starting pitcher Michael Pineda on the 15-day disabled list with a right flexor forearm muscle strain.
Severino is ranked as New York's No. 1 prospect by both MLB.com and Baseball America.
The 21-year-old signed with the Yankees in 2012 as an international free agent. He was promoted to Triple A in late May, where he has gone 7–0 with a 1.91 ERA and 0.929 WHIP in 61 1/3 innings. In his last start in the minors on Wednesday, Severino struck out 10 and did not allow a run in six innings.
Cashman said Severino will not have an innings limit in his MLB debut.
The Yankees play the White Sox in Chicago on Friday. New York currently holds a six-game lead in the AL East.
- Molly Geary