Tuohy scored his third try in as many GUINNESS PRO12 games against the Blues, with Ian Humphreys also dotting down, as Ulster remained unbeaten in this year's competition.
However, the Ireland international then left the field in the 61st minute clutching his right wrist, the same wrist he fractured while playing against Wales in February.
Despite Tuohy's starring role this season, Bell is adamant the strength throughout the team will allow Ulster to cope in the 29-year-old's absence and pointed to the pack's performance at BT Sport Cardiff Arms Park on Friday night as evidence.
"The game was won by our forwards," Bell told the Irish Times. "The set-pieces were rock solid and our driving line-out worked a treat.
"Cardiff really took it to us and threw their big ball carriers at us, but the defence was magnificent.
"Dan has been immense for us so far this season and has become our top try scorer. The injury is in the same arm in which he had a plate inserted following a previous injury and it doesn't look good.
"We don't want to pre-empt what might happen, but it looks as though he has broken it again. The good thing for us is that we have strength in depth in almost every position this season.
"It will be a huge blow for us if we do lose Dan, but the way the side played in beating a very competitive Cardiff Blues side we are moving in the right direction."
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