The West Midlands club were beaten 2-0 by non-league Luton Town in a pre-season friendly on Tuesday night and although Lambert wasn't too worried about the result, he was beginning to fret about the injuries to key players.
"We have too many injures at the minute. That's the frustrating thing," he told AV TV.
"When you look at the ones missing - the likes of (Jores) Okore, (Aleksandar) Tonev, (Gabby) Agbonlahor, (Andreas) Weimann, (Nicklas) Helenius - there are a lot of big players absent.
"We want to get them back.
"Hopefully there might be one or two back for Friday. We will have to see how that progresses and see how it goes.
"Once we start to get everybody back, we will be pretty strong.
"But you're going to get injuries. That's the nature of the game."