
The Foxes boss said his side were too young as they headed to a 4-0 home defeat in League One.
Leicester have three Albion prospects on loan but none started the game.
Harry Howell scored on his first league start for the club four days earlier as they beat Plymouth 2-0.
But he was on the bench this time along with Kamari Doyle and Tommy Watson.
Doyle, 21, went on at the break for Bobby Decordova-Reid, who is 33.
He was soon followed by 18-year-old Howell for Wes Burns, who is 31, on the right.
Watson, 20, entered the action at the same time as Howell but he replaced another youngster in 21-year-old Will Alves.
The changes involving Doyle and Howell appeared to be those to which Russell was referring.
He said: "I made a couple of subs and took some experienced guys off to try and inject some energy in the game.
"But the learning is, I think the team is too young and too inexperienced at the end. We were naive and too soft."
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Leicester’s midfield has been based so far around Sammy Braybrooke, 22, and Louis Page, 18, and both have impressed.
Albion always keep a close eye on how their young players are faring on loan.
Leicester are under pressure after a dismal start back in the third tier following two successive relegations.
They are away to Stockport County on Saturday.