The Detroit Lions were in man coverage and the Saivion Smith in coverage on Patriots TE Hunter Henry went down almost immediately with a serious injury.
Looked like he may have gone helmet-to-helmet with Hunter Henry at the line of scrimmage. Smith was joined in the ambulance by someone close to him who was attending the game. Stadium/security staff allowed the person on the field and to the ambulance from stands.
Photo courtsey of Dov Kleiman – Twitter