Scarlets' ace Parkes will qualify to play for Wales on residency grounds on December 2, the day of the final international of the year against South Africa.
The 30-year-old is one of five uncapped players to be selected by head coach Warren Gatland for the games against Australia, New Zealand, Georgia and the Springboks with Dragons hooker Eliot Dee, Dragons tighthead prop Leon Brown, and Ospreys pair Sam Cross (flanker) and Owen Watkin (centre) getting the call.
The selection of Parkes could spell the end of Roberts' 93-Test career after the Harlequins centre was omitted, along with a few other notable casualties in Scott Williams, Luke Charteris and Sam Davies.
There is a recall for Bath fly-half Rhys Priestland, who has been in excellent form for the Premiership outfit, while Rob Evans is included despite concerns over his fitness after failing his head injury assessment.
Justin Tipuric and Dan Lydiate are also injury concerns but have been named in the squad. Injuries will keep out skipper Sam Warburton, Ross Moriarty, George North and Gareth Anscombe.
"I'm really excited about this squad as we kick off the two year countdown to the 2019 RWC," said Gatland.
"We see this series as an opportunity to expose some players to the test environment and continue to build our game as we look ahead to two years time.
"This autumn is a lot different to 12 months ago, where the focus was all about rankings. We have selected five uncapped players, there are a further six who made their debuts on the summer tour so it is a big opportunity to see all these players in this environment and I'm looking forward to seeing what they are able to do."