The Tigers saw a £5m move collapse late on transfer deadline day, and both parties have blamed each other in the aftermath.
"I'm obviously bitterly disappointed that we didn't get Shane Long," Bruce told reporters. "That would have been the icing on the cake in terms of the squad we're trying to get together.
"We thought at one stage we were really, really close, but unfortunately it didn't happen. That's West Brom's prerogative, he's their player and they changed their mind for whatever reason.
"It would have been great for us if it happened, I'm a big admirer of the boy. I'm sure Shane is as disappointed as anyone, stuck at our training ground, left high and dry effectively."
When asked if he would return for the Republic of Ireland international, Bruce replied: "You never know what will happen in the next three or four months, but if he became available again of course I would be interested."
Long has scored 19 goals in all competitions since arriving at The Hawthorns from Reading in 2011.