Wallace, who was in the wars during Ireland's Grand Slam run, took another blow to the head early on in the province's recent home defeat to Cardiff.
Cave also shipped a knock late on in that 11-9 loss but is winning his fitness battle and looks poised to start alongside Ian Whitten, should Wallace be ruled out.
Ulster coach Matt Williams said: "Given the nature of the injuries, and in particular Paddy's situation in that it has happened before, we are waiting for expert opinion from the medics before making a decision."
The last time Ulster and Connacht met in the league was in November at Ravenhill, when Williams' charges recorded their largest victory of the season with a 40-point win.
Already assured of Heineken Cup qualification, Ulster will be gunning for a return to winning ways in Galway as they seek a mid-table finish to round off the 2008/09 season.
"We have a lot of respect for Connacht, they are a good side and play a hard game of rugby, but we are more determined than ever and we are going out to win," Williams said.
"We are on track for a mid-table finish to the season, and will be after maximum points from our last two fixtures to secure this."
The following players were not considered due to injury: Andrew Trimble, Bryn Cunningham, Paul Steinmetz and Thomas Anderson.
ULSTER Squad (v Connacht): Backs (11) - Isaac Boss, Darren Cave, Simon Danielli, Rob Dewey, Ian Humphreys, Paul Marshall, Timoci Nagusa, Niall O'Connor, Clinton Schifcofske, Paddy Wallace, Ian Whitten.
Forwards (14) - Rory Best, BJ Botha, Nigel Brady, Ryan Caldwell, Tom Court, Robbie Diack, Ed O'Donoghue, Willie Falloon, Stephen Ferris, Chris Henry, Matt McCullough, David Pollock, Daniel Roach, Bryan Young.