I assumed by modern era he meant the Premier League Never got to see Robson play sadly.
His player days did go into the first years of the PL tbf. Even if he was obviously passed his peak. Only made about 30 appearances for in the first two seasons, though did play a full season for Middlesbrough in 1996.
By modern I take it to mean the last 25 - 30 years. But that's just my interpretation. I'm old.