Middlesbrough boss Tony Mowbray believes Birmingham's struggles this season highlight the strength of the Championship.
Lee Clark's men currently lie in 14th place in the table, only seven points clear of the relegation zone having dropped out of the Premier League two seasons ago.
Mowbray told the club's official website: "Birmingham have had an up and down season.
"They're a big city club not long out of the Premier League, and I'm sure their supporters have high expectations.
"But they are not managing to achieve them at this moment in what is a very tough league."