Bolton has described his former premiership teammate as an "A-grader" while Lyon likened Parker to Geelong champion Jimmy Bartel and said he had become so important to Sydney he was now the club's second-best midfielder, behind Josh Kennedy.

Parker underlined his value to the Swans with a 33-possession, two-goal game against West Coast,  which earned him best afield honours on Sunday.

Parker is averaging almost 25 possessions a match and was one of the few Swans near the top of his game at the start of the season when the club stumbled out of the blocks.

Only Kennedy has found the ball more than Parker, who also ranks second at the club for contested possessions and clearances.

"He's got enormous upside still and playing a really consistent level like an A-grader, and that's what he is now," Bolton said.

"I'd definitely put him in All-Australian selection. His stats across the whole year are fantastic."

Lyon said the young Swan, who has been in the shadow of Kennedy, Kieren Jack, Jarrad McVeigh and Dan Hannebery, now deserved to be mentioned in the same catergory as that All-Australian quartet.

"He had to bide his time to get into that magnificent Sydney midfield, now I've got him as the No. 2 midfielder, behind Kennedy," Lyon said.

"That's in front of McVeigh, that's in front of Hannebery, [Lewis] Jetta, [Ben] McGlynn, [Nick] Smith and [Craig] Bird. I think he's an All-Australian at this point."

Adding to Parker's worth, he is a goalkicking midfielder and considered a very good mark for his size.

Of the league's top 50 ball-winners, only Adelaide's Patrick Dangerfield and Fremantle's Nathan Fyfe have taken more contested marks than the 184-centimetre Parker, and, with 16, he ranks equal sixth for goals.

"He's [like] Bartel in his ability to take a big high mark, and his contested footy I think is just of the highest, highest quality," Lyon said on the AFL website's program Access All Areas.

"But he plays different to Jimmy. He's even more inside than Jimmy and that's saying something because Jimmy is no fool in that area as well. Well done to [Parker], he's a star."

Bolton said Parker's marking ability made him difficult to defend against for opposition midfielders.

"He's taken some amazing marks, it comes from his basketball background as well," Bolton said. "He's got a good leap and a good spring, you have to contend with that if you're manning up on him."

Parker was the youngest Swan in the club's 2012 premiership and, with extra opportunities in the midfield, is posting career-best numbers in almost every key statistical area, according to Champion Data.

After playing much of his first three seasons primarily as a half-forward who drifted into the midfield, he is now a crucial part of an on-ball brigade regarded as one of the best in the league.

"The midfield has been red hot this year - that's their strength. You have all those topline players and at any stage they can rest or push forward and there's still tough contested footy around the ball," said Bolton, who retired last year.

"Teams need their A-graders and their second-stringers have to be willing to match it with these guys.

"He's one of the reasons I was always comfortable finishing up."

Parker was not a high draft pick but is proving an astute selection by the club's recruiting manager Kinnear Beatson, who was surprised the player lasted to pick 40 in 2010.

Bolton said the well-built Parker was a "man child" and adapted well to the Swans' physical style of play.

"He's always working hard both ways, it's amazing how it does open up for you if you're willing to put that pressure on," Bolton said.