Liverpool failed to win in the top flight during September and enter the Anfield fixture off the back of a disappointing 1-0 loss to Basel in the UEFA Champions League.
It leaves last season's Premier League runners-up in 14th with just seven points from their six games and Rodgers feels the departure of Luis Suarez to Barcelona has left a major void.
With Suarez gone and Daniel Sturridge having missed the past month with a thigh strain, Rodgers acknowledges the task Liverpool face in kickstarting their campaign.
"There was big change in the summer - and we lost a world class player," Rodgers explained on Thursday.
"We had to improve the squad and unfortunately we are in a period of transition again.
"It was difficult in my first few months but there was a vision that came through that.
"We know [Saturday] will be a tough game. They've got some very good players but, at home, we expect to win."
Sturridge's injury has sparked a club vs country row but the striker may return to action at Anfield, despite being left out of England's squad to face San Marino and Estonia, after Rodgers claimed the striker could "be available for some involvement".
However, Rodgers will be without Mamadou Sakho (thigh), Joe Allen (knee), Emre Can (ankle), Glen Johnson (thigh) and John Flanagan (knee).
While Liverpool have work to do to get their season up and running, West Brom appear to be making headway under Alan Irvine after a tricky start.
Irvine had to wait until the fifth league game of the season in for his first win but West Brom go into the fixture at Anfield following three consecutive victories.
A narrow 1-0 win over Tottenham at White Hart Lane was followed up by League Cup progression against Hull City before a resounding 4-0 rout of Burnley.
Saido Berahino has been at the heart of West Brom's upturn in form with three goals in his last two games and Irvine wants the England Under-21 international to keep it up on Merseyside.
Despite speculation over a senior call-up this week, Berahino was not drafted into Roy Hodgson's squad, although Irvine is confident that will not knock him off course.
"Saido's a very good professional so I can't see him getting carried away if he does get selected at full international level," Irvine explained.
"Saido's time will come. He may will be disappointed but I don't know.
"He might have been hoping after a lot of speculation this week but he'll handle all of that mentally - he's in a really good place."
Irvine is without Silvestre Varela (hernia), Brown Ideye (ankle) and Victor Anichebe (groin), while defender Andre Wisdom cannot face his parent club.
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