Eyebrows were raised when the west Londoners paid in the region of £11milion to sign McCormack from Leeds last summer following their relegation from the Premier League.
However, McCormack has impressed in west London, leading to reported interest from the likes of Norwich and Middlesbrough.
The Championship outfit acted to secure the 29-year-old’s future a fortnight ago as he signed a one-year contract extension until the summer of 2019.
That has not stopped the admiring glances, though, and Sheffield Wednesday have had a £10million bid rejected for McCormack.
Meanwhile, Wolves defender Richard Stearman is close to joining the Cottagers for a fee in the region of £2million.