Motie missed the 87-run first test loss in Pretoria with a lower back injury, but was able to bowl on the eve of the second game having recorded impressive match figures of 13-99 against Zimbabwe last month.
"He had a bowl yesterday and it went decent, so we will wait for the report and see," Brathwaite told reporters on Tuesday.
South Africa have selected two spinners in Simon Harmer (34) and Keshav Maharaj (33) on a wicket that has favoured the slow bowlers over the last 12 months.
"We have the option to bring him in if we can," Brathwaite added. "The wicket has some bare patches to the right-hander, so you can see why South Africa have gone with two spinners."
West Indies will be pleased with their bowling effort in Pretoria, bar a poor first couple of sessions after which they took the last 19 South African wickets in the match for 237 runs.
"It was very good for us as a bowling group to get 20 wickets," Brathwaite said. "It is as a batting unit where we can improve. South Africa will come hard at us and we have to be up for it.
"They are a tough team at home, and a bit more application, myself included, is needed from the batsmen. Will we change (the batting line-up)? Possibly not, we are backing the guys to get the job done.
"Test cricket is all mental. It is figuring out how to score runs against each bowler and is important to know with clarity which balls you want to play and what to leave.
"Mentally we have to be in the right space to believe we can bat and score runs. Then it is to do it."
West Indies have won one of 16 previous tests in South Africa, losing 13, while their overall record against their opponents is dire with three wins in 31 tests home and away.
