Bath's injured Faletau will not resume training until the middle of November.
Wales coach Rob Howley has included him in his squad for the four-match series.
"Wales need to find a different option and maybe give them a run of games through these matches that will provide Toby with competition," Delve said.
Faletau suffered a knee injury in September on his Aviva Premiership debut for Bath, who do not expect the British and Irish Lion to start training until the middle of November.
"Although it's a huge loss to Wales you have to weigh up the value of rushing him back for those possible last two games or get him completely fit and firing for the Six Nations and the Lions tour," added Delve, who also played for Bath.
Wales play Australia in Cardiff on 5 November, followed by Tests against Argentina and Japan, concluding against South Africa at the Principality Stadium on 26 November.
Faletau and his likely replacement Ross Moriarty of Gloucester would not be available for the opening game against Australia.
The game falls outside World Rugby's international window and Premiership Rugby will not sanction the release of English-based Welsh players.
Northampton Saints wing George North, Harlequins centre Jamie Roberts and Bath pair Luke Charteris and Rhys Priestland will also be unavailable for the Wallabies game.
Ospreys fly-half Sam Davies has been included in Howley's squad after his recent performances for the region.
"I think Sam has really put himself in the mix. His early season form has been fantastic," said Delve, a former Ospreys team-mate.
"It's a nice headache to have and it will be interesting to see if Sam Davies does get a run through the course of the four games.
"Whether he gets the opportunity to get that backline moving in the way that Rob has said he wants to evolve."
Taulupe Faletau's absence at the start of the autumn internationals presents an opportunity for another forward to stake a claim for Wales, says former number eight Gareth Delve.