The New Zealander was the last opponent for Joshua, losing his WBO belt on a unanimous decision defeat in March, and the British heavyweight star makes his next title defence against Alexander Povetkin at Wembley on Saturday, live on Sky Sports Box Office.
Parker endured more anguish in July, suffering another points loss after Dillian Whyte survived a last-round onslaught, although the 26-year-old still believes he can fight his way back into world title contention.
“Yes of course I will watch,” Parker told Sky Sports. “I will be observing their styles closely. I expect Joshua to win, but anything can happen in boxing.
“It is frustrating. I would have loved a rematch with Joshua at Wembley, and I believe I am still in the frame, being the only pro to take him the distance.”
After being floored for the first time in his career, Parker staged a late fightback and seemed to be on the brink of stopping Whyte, who clung on for a victory which dealt a blow to the Kiwi’s hopes of receiving an April bout with Joshua at the national stadium.
“Another 30 seconds and I would have beaten Dillian Whyte and would be fighting Joshua at Wembley,” said Parker. “But that’s boxing and I must earn my way back.
“I will fight someone before the end of the year.
“As for Whyte, everyone wants to see a rematch and we should have got it on straight away. We will fight Whyte again as soon as he is willing.”
Joshua has been locked in talks with WBC champion Deontay Wilder, even before the fight with Parker, but the former WBO king does not believe AJ will have been unsettled by the speculation as the American instead accepted a challenge from Tyson Fury.
“No Joshua won’t be distracted,” said Parker.
“He is a professional and will be focused on what is in front of him.”
Watch Joshua vs Povetkin, at Wembley Stadium, on September 22, live on Sky Sports Box Office, from 6pm. Book via your Sky remote or book it online here.
Even if you aren’t a Sky TV subscriber you can book and watch it at skysports.com/boxofficelive.