Brendan Rodgers' side were in the running for a Champions League spot before a stuttering end to the season saw the Foxes claim a Europa League position instead.
As for the Baggies, it was a dramatic final day in the Championship which saw Slaven Bilic's side finish in second position and gain automatic promotion to end the club's two-year Premier League absence.
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Conor Townsend and Kenneth Zohore are the only doubts for West Brom boss Slaven Bilic, who otherwise has a full squad at his disposal.
Summer signings Grady Diangana, David Button, Callum Robinson and Cedric Kipre are all available for the opening fixture.
For Leicester, however, it's a different story. Rodgers is still without star right back Ricardo Pereira, while Christian Fuchs and Jonny Evans will also miss the start of the new season.
Influential creative midfielder James Maddison is also expected to be sidelined, along with club captain Wes Morgan.
West Brom: Johnstone; O'Shea, Ajayi, Bartley, Gibbs; Livermore, Sawyers; Diangana, Pereira, Grosicki; Robinson.
Leicester: Schmeichel; Justin, Ndidi, Soyuncu, Castagne; Mendy; Perez, Tielemans, Praet, Barnes; Vardy.
Despite their form across the season earning West Brom automatic promotion from the Championship, the Baggies managed just three wins in their last ten competitive outings.
While the effects of a long, draining season undoubtedly took its toll on the squad, Bilic needs his side to hit some form early in their Premier League campaign.
As for Leicester, the Foxes also ended an impressive season in poor form, winning just a handful of their final ten competitive fixtures. They were even thumped 4-1 by the eventually relegated Bournemouth.
With the club now in the Europa League, Rodgers will look to get the points on the board quickly in domestic action before the squad board midweek flights to the outskirts of Europe.
West Brom 2-2 Queens Park Rangers (22/7)
Huddersfield 2-1 West Brom (17/7)
West Brom 0-0 Fulham (14/7)
Blackburn Rovers 1-1 West Brom (11/7)
West Brom 2-0 Derby County (8/7)
Leicester 0-2 Manchester United (26/7)
Tottenham 3-0 Leicester (19/7)
Leicester 2-0 Sheffield United (16/7)
Bournemouth 4-1 Leicester (12/7)
Arsenal 1-1 Leicester (7/7)
Leicester would be expected to prevail on Sunday given the extra quality that they have in their side, even with their injury woes, and the likes of Tielemans and Praet should be able to craft opportunities.
There's no doubt West Brom will make the Foxes work, and it could be a tough afternoon for Rodgers' side. The Baggies will have to take the chances that fall to them, however, as Jamie Vardy is always on the prowl.
In what could be a tight game, a player like Vardy could be decisive in deciding which team ends the day with three points.
Prediction: West Brom 1-2 Leicester