The Baggies have taken 10 points from their opening four games and sit second in the table, while the Posh have made a steady start to life back in the second tier with four points; placing them 17th.
Match preview
Valerien Ismael fielded a very young side in West Brom's EFL Cup tie against Arsenal in midweek, a decision that backfired as they were thrashed 6-0.
The French boss made 11 changes from last weekend's league win over Blackburn Rovers and handed out six debuts, so the defeat is unlikely to hamper the morale of the squad's first choice XI.
The team selection made it clear that the Championship is the priority for the Baggies this season as they aim to secure an immediate return to the Premier League.
That mission has certainly got off to a strong start, as victory over Rovers last Saturday followed wins against Luton Town and Sheffield United and the opening day draw with Bournemouth.
West Brom are the Championship's highest scorers at this early stage of the season with 11 goals to their name spread between five different players.
That will be a warning sign to Peterborough who have conceded seven times so far - only Luton and Reading have let in more goals.
Darren Ferguson admitted that last weekend's 1-0 defeat to Preston North End was "a very disappointing result" as they handed the Lilywhites their first points of the season.
The Posh will be pleased to get back to the Weston Homes Stadium as they had the best home record in League One in 2020-21, and all four of their points this season have come in Cambridgeshire; a 2-1 win over Derby County and a 2-2 draw against Cardiff City.
This will be the first league meeting between Peterborough and West Brom since the 2009-10 season, when the Baggies won both matches on their way to promotion to the Premier League.
The Midlands outfit are unbeaten in their last eight games against the Posh, dating back to January 1994.
Peterborough United Championship form:
Peterborough United form (all competitions):
West Bromwich Albion Championship form:
West Bromwich Albion form (all competitions):
Team News
Peterborough continue to be without captain Mark Beevers in defence, meaning Josh Knight will deputise as he did last weekend.
Jack Marriott is continuing to build up his fitness and played an hour for the Under-23s in midweek, so may be handed a start.
Fellow striker Jonson Clarke-Harris scored 31 goals in League One last season but is yet to get off the mark in four games in the Championship.
West Brom have been dealt a blow with the news that Callum Robinson, who has scored three Championship goals already, has tested positive for coronavirus and will therefore miss Saturday's game.
Grady Diangana is the most likely option to replace him in the Baggies' frontline, while Jordan Hugill signed on loan from Norwich City this week and could make his debut.
Valerien Ismael has confirmed that Matt Clarke will be out for five or six weeks after suffering a hamstring injury against Blackburn, so Semi Ajayi should start at centre-back.
Peterborough United possible starting lineup:
Pym; Kent, Thompson, Knight; Ward, Grant, Norburn, Butler; Szmodics; Dembele, Clarke-Harris
West Bromwich Albion possible starting lineup:
Johnstone; O'Shea, Bartley, Ajayi; Furlong, Mowatt, Livermore, Townsend; Diangana, Phillips, Grant
We say: Peterborough United 0-3 West Bromwich Albion
Callum Robinson will certainly be a big miss for West Brom, but the Baggies should still have enough quality in their side to overcome Peterborough, who may be taught a lesson about the harsh reality of life in the Championship.