According to Lindsey Adler of The Athletic, he won't resume baseball activities for another five weeks as he recovers from a Grade 2 lat strain:
Severino had initially been kept out of action after suffering inflammation in his right rotator cuff during spring training, per James Wagner of the New York Times. Last week, the Yankees announced that he had suffered the lat injury, furthering his rehabilitation time.
The starting pitcher said he didn't know why an MRI didn't previously uncover his lat injury:
He was initially expected to return at some point in May, but this latest news suggests he'll be out of action until at least June and perhaps longer than that.
It's a big blow for a Yankees team that has been decimated by injury, with Miguel Andujar, Dellin Betances, Didi Gregorius, Aaron Hicks, Gary Sanchez and Giancarlo Stanton among the 12 Yankees on the injured list.
Severino, 25, was expected to be the ace of a strong rotation that also includes James Paxton and Masahiro Tanaka. He went 19-8 in 32 starts last season (191.1 innings) with a 3.39 ERA, 1.15 WHIP and 220 strikeouts. It was his second straight season throwing at least 190 innings and 220 strikeouts.
Instead, injuries have forced the Yankees to use six different starting pitchers this year, including Domingo German and Jonathan Loaisiga. The team has tread water given its injury woes, starting 7-9, but getting key players back in action like Severino will be crucial going forward.