The duo's battles in the northern Europe were the highlight of the first half of the season, with BMC's Van Avermaet recording near-domination of the cobbled Classics.
The Belgian won Omloop Het Nieuwsblad, E3 Harelbeke, Gent-Wevelgem and Paris-Roubaix, while he claimed second place at the Tour of Flanders.
World champion Sagan, meanwhile, won Kuurne-Brussels-Kuurne and finished second behind Van Avermaet at Het Nieuwsblad. He also came second at Milan-San Remo.
There are nine stages at the Tour de Suisse and though predominately mountainous - stages four to seven all take place in the high mountains - there are three stages were it is likely the pair will go directly head-to-head.
Sagan, leading his Bora-Hansgrohe team, will fancy his chances on stage two, a hilly circuit race starting and finishing in Cham. Including four ascents of a long, but shallow climb, the race ends with a slight uphill finish, and if the breakaway is reeled in, and the GC riders hold back, Sagan will be eyeing victory.
Stage three, ending in Bern, finishes with a bigger uphill finish than the preceding stage, but it isn't unfeasible that Sagan and Van Avermaet will be tangled in a sprint for the win.
Stage five includes the huge climb of Simplonstrasse, but the fact that it reaches its near-2000m summit at 120km and then a flatter parcours follows, it opens up the possibility that a sprint between the Classics specialists and rouleurs could occur.
The fourth and final stage where we could see the world and the Olympic road race champions fight it out for stage honours is stage eight, which features an undulating circuit.
However, with the general classification likely to be in play, the climbers and overall riders may prevent a stage win for Van Avermaet and co.
However many stages the pair battle directly against each other, every cycling fan will be pleased to see them back in the same races.
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