Guess he'll break Gareth Barry's record at some point next season. There are few players that are still active and playing in PL that make top 100 in PL performances: Ashley Young is on 22nd place (452 performances), Kyle Walker 47th (394 performances), Ward-Prowse 53rd (379 performances), Jonny Evans and Sterling joint 56th (378 performances), Lukasz Fabianski 72nd (362 performances) and Danny Welbeck 96th (332 performances).
Ward-Prowse is 29 so perhaps could get to 500+ performances but it'll probably be long before someone breaks James Milner's record. 650+ PL appearances is crazy. Wonder if he could reach 700+. It'd mean playing at least another season after next one.