In Pienaar's absence, Ulster have moved to the top of the RaboDirect PRO12 table with Paddy Jackson and Niall O'Connor sharing the workload at fly-half and Paul Marshall and Michael Heaney doing similarly at scrum-half.
But Pienaar's contributions to Ulster's cause cannot be overstated and he played an instrumental role in their march to the Heineken Cup final last season, producing a flawless kicking display in howling winds in the quarter-final victory over Munster.
And Best, who has featured in just one of Ulster's RaboDirect PRO12 matches this season, is relishing seeing Pienaar back in action.
"It definitely gives us a lift. A few things this year have been very strange for Ulster. We haven't yet managed to put the same XV out in successive games," Best told the Irish Independent.
"Usually you get your best XV and play them every week because you feel that's all you've got.
"Every week we've added an international piece to the jigsaw and Ruan coming in this week is the final piece in the jigsaw.
"Ruan is a very popular guy, not only for what he does on the pitch, but for what he adds off it."
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