Yankees encouraged about Luis Severino's progress: 'There’s just a confidence he's exuding'During first bullpen session, Aaron Boone said, 'Hey, back off a little bit. It’s coming out too well'3/11/2021, 4:05 PMScott ThompsonEditorial ProducerFeb 20, 2020; Tampa, Florida, USA; New York Yankees starting pitcher Luis Severino (40) poses for a photo during media day Mandatory Credit: Butch Dill-USA TODAY Sports / © Butch Dill-USA TODAY Sports