Ireland internationals Paddy Wallace and Andrew Trimble are not available for the match after they each fractured a thumb in the away defeat to Leinster last weekend.
This opens the way for Darren Cave to return to the starting line-up after an impressive appearance as a replacement against Leinster. He will wear the number 13 jersey with Nevin Spence switching to inside centre to accommodate him.
Botha's South African colleague Johann Muller returns to the second row after missing the trip to Dublin with a dead leg, meaning Tim Barker has to settle for a place among the replacements.
Scotland's Simon Danielli will occupy the left wing spot so Craig Gilroy, who has now scored eight Magners League tries, moves to the right wing position vacated by Trimble.
Willie Faloon will start at openside flanker, with Chris Henry moving to the blindside and Robbie Diack dropping to the bench.
Adam Macklin is named on the bench too, and may taste his first action since breaking an ankle playing for Ulster Ravens last September.
The defeat against Leinster means Ulster must now win their two remaining games to guarantee a semi-final spot.
Ulster and Connacht played out a 15-15 draw at the Sportsground in September, but Brian McLaughlin will be hoping the Ravenhill factor will prove decisive as Ulster have won their previous six home games in all competitions.
"It's an interpro and we'll be up for it. We're at Ravenhill and we want to perform," explained the Ulster boss.
"Connacht are playing a lot more rugby than they used to but they're still very aggressive and very physical, so if we don't turn up they'll cause us problems.
"If we fall below our optimum level, then we struggle. But if we're at our best we can beat the best, so that's what we'll be looking to do on Friday night.
"It might be our last game (of the season) at Ravenhill and the boys have a point to prove. We're looking forward to getting out there and doing our job well."
Ulster Rugby would advise supporters coming to the game (gates open 5.30pm) to avoid parking in the immediate vicinity of the Ravenhill grounds and that the following roads are only accessible for residents and closed to everyone else: Onslow Parade, Ravenhill Park and Ravenhill Park Gardens.
There will also be parking restrictions in place in the Castlereagh area (Mount Merrion Avenue). Supporters are encouraged to make use of the Park 'n' Ride facilities at Pirrie Park and along Montgomery Road.
ULSTER (v Connacht): Adam D'Arcy; Conor Gilroy, Darren Cave, Nevin Spence, Simon Danielli; Ian Humphreys, Ruan Pienaar; Paddy McAllister, Rory Best (capt), Jerry Cronin, Johann Muller, Dan Tuohy, Chris Henry, Willie Faloon, Pedrie Wannenburg.
Replacements: Andi Kyriacou, Bryan Young, Adam Macklin, Tim Barker, Robbie Diack, Paul Marshall, Ian Whitten, Conor Gaston.