But head coach Fabian Hurzeler is unsure whether others will emulate him in playing in the top flight at 40.
Milner will be in the matchday squad as Albion face Crystal Palace on Sunday.
He is currently on 652 Prem appearances, one behind Hastings-born Gareth Barry.
If he gets on against Palace, he could take the record outright in midweek away to Aston Villa, a club for whom both he and Barry played.
Albion boss Hurzeler said: “What is definitely special is his body and what is definitely special is his approach and his discipline.
“When you see him working on a daily basis, it's incredible. He's taking care of very small margins, taking care of nutrition, of his gym sessions.
“It's not a surprise that he's that fit for his age. I think other players can definitely do it, but you need to have the right mindset and you need to have an incredible high discipline and professionalism and an incredible high desire and hunger to keep going, to keep being successful
“I think he proved it in his whole career that he has this hunger and desire inside of him and that's what makes him so special.”
Milner’s last two appearances, off the bench against Fulham and Everton, have been contentious among many Albion fans as late points were dropped.
But Hurzeler said he has again been training well this week.
“I think it (the record) will be a special thing for him but he is focussed on the ambitions of the club as well.
“He wants to be always successful, like he was his whole life.
“He is a driver of this winning mentality and I think it is very important to have these kinds of players in the squad. They know how to win.”