Strasburg came into the league throwing 98 mph when the mlb average FB velocity was 90.5. In 2019, he was averaging 93.9, while the league average was 93.1. The league average is getting close to 94 this year. If he's going to improve from his 90.3 fb velocity from his first start, it's tough to imagine that he can be even a replacement level pitcher going forward.
I'm not too worried about velocity. He has always had incredible secondary pitches. Problem is endurance and control.