Bradley Wiggins says it is "more than likely" he will sacrifice defending his Tour de France title to support team-mate Chris Froome in the 2013 race.
The route, revealed on Wednesday, is mountainous and will suit climbers such as Froome and Alberto Contador more than time-trial expert Wiggins.
"It's more than likely I'll ride in a supporting role for Chris," Team Sky rider Wiggins said. "I just want to be in a successful team."
"My objective will be the Giro."
Wiggins, 32, became the first Briton to win the prestigious race this year, taking the yellow jersey ahead of runner-up Froome.
But Kenyan-born Froome, 27, looked stronger than Wiggins in the mountains at times and, in a memorable moment, was ordered back to assist his team leader after breaking clear on Stage 11.
Wiggins appears more suited to next May's Giro d'Italia, which is less mountainous and includes more than 90km of time trials.
Next year's Tour de France - the 100th edition - will begin on the French island of Corsica on 29 June and end with an evening finish on the Champs-Elysees in Paris on 21 July, with the riders having cycled 3,360km.
There are several tough ascents, with Stage 18 featuring two climbs up Alpe d'Huez, while the length of the time trials has been reduced to 65km from 100km in 2012.
Team Sky principal Dave Brailsford said he would study the route in detail before coming to a decision about team leadership.
"We've very fortunate that we've got Bradley and Chris in the same team," he told BBC Sport.
"We'll have a look at the route and the rest of the races throughout the season and then we'll decide on our strategy to try and win as many races as possible."
The 2013 Tour contains three time trials - two individual and one for teams - as well as four summit finishes, not least a climb to Semnoz in the Alps on the penultimate day, which may determine the winner.
There is a chance for British sprinter Mark Cavendish, who has left Team Sky for Omega Pharma-QuickStep, to claim the first yellow jersey of his career on the relatively flat opening stage from Porto Vecchio to Bastia.
However, a Tour that also includes climbs up Ax 3 Domaines in the Pyrenees, as well as Mont Ventoux, is likely to favour the climbers.
Spaniard Contador, who won the Tour in 2007 and 2009, did not take part in the 2012 edition as he was serving a two-year doping ban, while Luxembourg's Andy Schleck - crowned champion in 2010 after Contador was stripped of his title - missed out through injury.
Cavendish, who sits fourth on the all-time list with 23 stage wins in the Tour, including four in a row on the Champs-Elysees finale, said on Twitter: "Well, a spectacular course for 2013 Tour de France.
"Very hard route, book-ended with 2 beautiful sprint days in Corsica & twilight in Paris."
The Tour will be the first since for doping.
Tour de France 2013 route
29 June - Stage 1: Porto Vecchio - Bastia, 212km
30 June - Stage 2: Basta - Ajaccio, 154km
1 July - Stage 3: Ajaccio - Calvi, 145km
2 July - Stage 4: Nice - Nice, team time trial, 25km
3 July - Stage 5: Cagnes sur Mer-Marseille, 219km
4 July - Stage 6: Aix en Provence - Montpellier, 176km
5 July - Stage 7: Montpellier - Albi, 205km
6 July - Stage 8: Castres - Ax 3 Domaines, 194km
7 July - Stage 9: St Girons - Bagneres de Bigorre, 165km
8 July - Rest day, St Nazaire
9 July - Stage 10: St Gildas des Bois - St Malo, 193km
10 July - Stage 11: Avranches - Mont St Michel, individual time trial, 33km
11 July - Stage 12: Fougeres - Tours, 218km
12 July - Stage 13: Tours - St Amand Montrond, 173km
13 July - Stage 14: St Pourain sur Sioule - Lyon, 191km
14 July - Stage 15: Givors - Mont Ventoux, 242km
15 July - Rest day, Vaucluse
16 July - Stage 16: Vaison la Romaine - Gap, 168km
17 July - Stage 17: Embrun - Chorges, individual time trial, 32km
18 July - Stage 18: Gap - Alpe d'Huez, 168km
19 July - Stage 19: Bourg d'Oisans - Le Grand Bornand, 204km
20 July - Stage 20: Annecy - Annecy Semnoz, 125km
21 July - Stage 21: Versailles - Paris