Provisional entry lists for the FIA World Endurance Championship and the 24 Hours of Le Mans released last week suggest a shift in focus towards the top tier of GT endurance racing.
When Audi closed down its LMP1 Hybrid programme late last year, this year's premier prototype class was always going to be thinner.
The top category becomes a Porsche versus Toyota duel this year but the effect of Audi's withdrawal gets softened by Toyota confirming it will run three of its revamped TS050 Hybrids at Le Mans and at the Spa-Francorchamps round.
Toyota's No7 car will be crewed by Mike Conway (GB) and Kamui Kobayashi (Japan) who will be joined by new recruit Jose Maria Lopez of Argentina, the three-time World Touring Car Champion with Citroen.
Sebastien Buemi (Switzerland), Anthony Davidson (GB) and Kazuki Nakajima (Japan) remain as an unchanged line-up for the No8 Toyota while Stephane Sarrazin (France) will anchor the third car at Spa and Le Mans with two drivers still to be confirmed.
Defending WEC title holder Porsche will run two 919 Hybrids in an upgraded specification and has reshuffled its driving squad following the retirement of Mark Webber.
For Kiwi fans that means LMP1 interest levels are doubled this year with 2015 Le Mans winner Earl Bamber gaining a fulltime place in the Porsche squad as Webber's successor alongside fellow Kiwi Brendon Hartley and Germany's Timo Bernhard.
Swiss driver Neel Jani is the only driver retained from Porsche's 2016 Le Mans and WEC title-winning trio and will be joined by Nick Tandy (GB) and former Audi driver Andre Lotterer (Germany).
With the Swiss Rebellion Racing team moving to the LMP2 category, the only other LMP1 entry is ByKolles Racing with a revamped car powered by the V6 engine originally developed for the 2015 Nissan LMP1 project.
The main interest in this car is the presence of former F1 star Robert Kubica (Poland) returning to top-line racing after a foray into rallying.
The LMP2 category features new rules -- four different chassis are eligible and a new 4.2-litre Gibson Technology V8 engine is specified -- and will see 10 cars contest the full season. But the LMP2 grid grows to an impressive 25 entries at Le Mans with most teams from the FIA European Le Mans series joining the grid.
The full-season WEC GTE-Pro entry count is eight cars -- two each from Porsche, Ford, Aston Martin and the AF Corse team which carries Ferrari's hopes.
The Ford GT and Ferrari 488 GTE enter their second season in the GTE-Pro class while Porsche introduces a new-generation 911 RSR with the engine and gearbox location switched from traditional 911 layout to provide a mid-engine configuration.
The Aston Martin Vantage V8 goes into its last season with a new car planned for 2018 when the GTE-Pro category is also set to gain BMW as a factory team.
At Le Mans the GTE-Pro grid is boosted to 13 cars with the Ford GT effort expanded to four cars (as it was in 2016) and the return of the US-based Risi Competizione Ferrari 488 -- the closest challenger to the Ford armada in 2016.
Corvette Racing team will make its annual trip to Le Mans with a pair of rumbling Corvette C7.R machines.
The full-time FIA WEC entry list for 2017 comprises 28 cars -- five in LMP1, 10 in LMP2, eight in GTE-Pro and five in GTE-Am.
The field of 60 cars announced for Le Mans in mid-June comprises six LMP1 cars, 25 in LMP2, 13 GTE-Pro and 16 GTE-Am crews.
2017 FIA World Endurance Championship
April 1-2: Prologue, Monza, Italy
April 16: 6 Hours of Silverstone, GB
May 6: 6 Hours of Spa-Francorchamps, Belgium
June 4: 24 Hours of Le Mans Test Day, France
June 17-18: 24 Hours of Le Mans, France
July 16: 6 Hours of Nurburgring, Germany
September 3: 6 Hours of Mexico City, Mexico
September 16: 6 Hours of Circuit of the Americas, US
October 15: 6 Hours of Fuji, Japan
November 5: 6 Hours of Shanghai, China
November 18: 6 Hours of Bahrain