Mashego and Sibisi have been at Swallows since Tuesday, and have both been told to remain after a few other players who were on trials, including Sibusiso Mahlangu, were told to return next week.
Word from within the Swallows camp is that Mashego and Sibisi have shown that they could be of use to The Birds, whose squad needs some depth.
The club is already contemplating bringing the duo on board, but are currently weighing up their budget as both players were on good packages at their previous clubs.
Both Mashego and Sibisi are currently free agents and will not be affected by the transfer window closing at the end of the month.
Swallows have just four strikers in their squad, Siyabonga Nomvete, Mpho Maleka, Cheick Cisse and Lerato Chabangu, though Chabangu is more effective coming from the flanks, and the chance of both Mashego and Sibisi signing is high.