The Blues boss is expected to renew his interest in Arsenal centre-back Upson after Sunday's match with The Gunners at St Andrews.
"At the start of the season, I said the one thing we needed was a bit of luck with injuries or suspensions and that hasn`t happened in recent weeks," said Bruce.
"It`s been paramount that we got some bodies in and thankfully the board have allowed me to do that.
"We still hope there could be another one and possibly two to give us every possible chance of staying in this division," he added.
"The club are ambitious and want to stay in the Premiership and I think it again shows our intentions with the signings of Clemence and Clapham. The two of them are proven quality and it will be a huge lift to the squad.
"The squad have done really well but we needed to get extra strength in depth and they will be valuable members for us."