Prior announced he was taking a break from cricket for the rest of the season following England’s defeat to India in the second Test on Monday.
The 32-year-old – who was replaced in the squad by Jos Buttler yesterday - intends to have surgery to cure his Achilles problems before returning to try to win his place back next year.
Robinson said: “The media have hunted him mercilessly and made his position very difficult.
“Everybody scrutinises every move he makes to the extent that it almost makes it impossible to do his job as he is under so much pressure.
“But Matt is a warrior. He is only 32 and some of the obituaries that have been written about him are a bit premature.
“He has a lot of international cricket left in him so he will take stock and then hopefully come back strong and get himself available for those Test matches in April.”
Sussex all-rounder Chris Jordan has kept his place in the England squad for the third Test at the Ageas Bowl on Sunday.