Championship leader Andreas Mikkelsen was set to headline the thrilling entry, however, the Toksport pilot was sidelined at the very last minute after a positive Covid-19 test result prevented him from travelling to Porto.
With Mikkelsen out of the picture, the opening is there for rivals to reduce his 35-point advantage.
Two of the drivers expected to challenge for victory this week are Esapekka Lappi and defending champion Mads Østberg. Although both have WRC2 wins already to their name in 2021, Portugal will be the first time the pair go head-to-head this season.
Lappi will drive a Movisport-prepared Volkswagen Polo GTI R5 for the first time since his Finland victory in February, whilst Østberg wheels out a Citroën C3 Rally2 fresh from a win at the Croatia Rally.
Portugal holds special memories for the Østberg as he claimed his first and only outright WRC rally win here in 2012.
Amongst the drivers hoping to shake up the standings is Hyundai i20 R5 youngster Oliver Solberg. The 19-year-old stunned in Finland when he claimed seventh on his World Rally Car debut and will be one to watch as he kicks off his 2021 WRC2 campaign.
Toksport’s hopes rest on the shoulders of Bolivian hotshot Marco Bulacia, who will be aiming to score big on his preferred surface. Bulacia currently holds second in the standings behind his absent team-mate.
M-Sport Ford star Teemu Suninen has also entered a Fiesta Rally2 car and hopes to improve on his Croatia performance where he finished second. The Finn believes driving the second-tier car will stand him in good stead ready for the switch to new hybrid-generation Rally1 cars in 2022.
Other entries include Nikolay Gryazin, who crashed out of the battle last time out, in a second Movisport Polo, as well as flying Frenchman Eric Camilli in a Citroën. Hyundai junior Ole Christian Veiby also starts in an i20.
Tom Kristensson will help fly the M-Sport Ford flag following a dramatic crash on his Croatia debut in April which saw his Fiesta roll down a bank, with experienced Czech driver Martin Prokop set to pilot a similar car.
Estonian youngster Georg Linnamäe is a non-starter after his co-driver Volodymyr Korsia positive for Covid-19 on Sunday.
Full coverage from Vodafone Rally de Portugal will be available on WRC+ All Live here, including every stage broadcast as it happens as well as key interviews, features and expert analysis from the service park.