Antonio Luna and Andi Weimann are both targeting a return to action for the Monday night clash at The Hawthorns after suffering from hamstring injuries, as is Fabian Delph (knee).
However, it is feared Birmingham-born Gabby Agbonlahor (ankle) could be in danger of missing out, although Gary Gardner (back) could resume training after the international break.
Joe Bennett (back), Jores Okore (knee) and Charles N'Zogbia (achilles) are out injured while Ciaran Clark (foot tendon) pulled out of Republic of Ireland squad on Sunday, but should be fit to face Albion.
Despite the loss of many of his key players, Lambert was pleased with his side's 2-0 victory over Cardiff City at the weekend, which lifted them into 11th spot in the Premier League.
"When you look at the side we put out we've got a lot of injuries," he told the Birmingham Mail. "We've got nearly half a team out.
"You know things are really bare when you're putting two young kids (Daniel Johnson and Callum Robinson) on the bench."
The Scot is also hopeful that Delph will return from a knee problem to face an in-form Baggies team who have already beaten Manchester United at Old Trafford and held Chelsea at Stamford Bridge this season.
"I think he'll be okay for the West Brom game," confirmed Lambert. "I think we've caught the international break at the right time.
"It's a big, big ask. I knew we had to try and get through this one. Thankfully we seem to have done it with a win.
"If we get three or four of them back for the West Brom game, then good."