The Tigers have been left short of attacking options after new signing Robert Snodgrass was ruled out for six months after dislocating his kneecap in the club’s 1-0 win over QPR.
Republic of Ireland international Long was signed by Premier League rivals Southampton for a fee of £12million just seven months after joining Hull in a £6.5m deal from West Bromwich Albion.
Aboubakar is a Cameroon striker who netted 16 goals in Ligue 1 last season, a total that was only bettered by Zlatan Ibrahimovic.
Bruce confirmed the 22-year-old was one of a number of players the club are considering as they look to bring in reinforcements before the transfer window closes.
"We haven't made an offer, no,” the Tigers boss revealed.
“We've had conversations but we've had conversations with between six and eight different clubs over six or eight different players. We're trying to add to the squad as we know we have to.
“We've lost two players in the last week, big players in Long in which we've gone on record as saying the offer was just too good to turn down.
“But we didn't envisage losing Snodgrass for six months which is a huge blow to us because he was brought in to give us that little bit of quality which we needed to the midfield area.
"It's been a huge blow over the weekend but hopefully we've got 10 to 11 days to bring in a replacement.
"Two or three offers went out yesterday and we'll see what materialise but I'm not going to tell you who."