The Leicester City hitman yesterday completed a loan move to Brighton, leaving Villa to focus on alternatives ahead of tomorrow’s deadline.
Bolstering his options in attack was Bruce’s primary aim for the window only a few weeks ago.
But Scott Hogan’s excellent form and the return to fitness of Gabriel Agbonlahor means the need is now less pressing, while the manager is also wary of blocking the development of youngsters Keinan Davis and Rushian Hepburn-Murphy.
“It’s my job to improve the squad. If there is someone who can do that, we’ll do it,” said Bruce.
“But I am not just going to dive into the market for the sake of it because then it is no use. I would rather give Hepburn-Murphy a go, give Keinan a go.
“To be fair, until the last month, Keinan led the line fantastically well. He’s now had a break for a month. The urgency I once had (to bring in a striker) is no longer there.”
Bruce was hopeful of landing Ulloa earlier in the month but the Argentine opted to re-join Brighton, for whom he scored 26 goals in 58 appearances between 2013 and 2014.
Defender Tommy Elphick has joined Reading on loan for the rest of the season, while Aaron Tshibola has made the move to Kilmarnock.
Manchester United’s Axel Tuanzebe remains Villa’s only addition of the window.
Bruce said: “We had two particular targets. One has come off, one has gone to Brighton.
“Ideally, everyone would probably like four (strikers). But unless there is a someone around who I think will be different to what we have got. At the moment we are not close to anything.”