It does not take an expert to watch Josh Rosen set up and throw to determine he is a gifted passer. It does, however, take real foresight to determine if Rosen is a perfect fit for the Giants, who own the No. 2-overall pick in next month’s draft. One of, if not the most impressive and perhaps most unappreciated (outside of the Giants building) of Eli Manning’s attributes for the past 14 years is his remarkable, at times astonishing durability. Rosen comes out of UCLA with a few injury issues that cannot be discounted but also must be put in proper perspective. It is interesting that earlier in the week, new Giants head coach Pat Shurmur, when asked if anything he learned from studying every Manning snap in 2017 troubled him, immediately pivoted to something he once spoke about with former NFL executive Bill Polian. “He’s the guy who told me guys who get injured a lot continue to get injured a lot,’’ Shurmur said. Now, then, it is unfair to characterize Rosen as a guy who gets injured a lot. But he has a medical history that is not unblemished. Shurmur, unsolicited, was eager to point out Manning has thus far been invulnerable in his NFL career.