Summer signing Alcaraz has yet to feature this season after undergoing groin surgery pre-season, while Pienaar has missed the last four games with a hamstring problem.
Martinez is happy with the progress the pair are making on their injuries and refused to rule them out of next week's Premier League clash with Hull City
"Stevie has reacted really well to treatment and he is progressing extremely well," said Martinez.
"Antolin Alcaraz has had a very good period as well, so, all in all, those two have benefited enormously from this international break.
"We don't want to put a date on it. We are very much seeing their reaction and seeing how quickly they can take the workload on.
"In medical terms, they shouldn't be fit for Hull, but I would not say they cannot make it.
"There's still a question mark over them but Steven is a litle bit ahead.
"It's been really positive to see them with big smiles and enjoying their work."