However, the Celtic technical team will be observing Mothatego until May or June, before the final decision is taken by Siwelele, whether to conclude the deal or not.
"We have agreed a deal in principle. But it is subject to Bloemfontein Celtic monitoring Jackie Mothatego in competitive games until the end of the season," Wasserfall told Goal.
The 27-year old midfielder who impressed the Celtic technical team during his trial spell early this year, is a regular for the Botswana national team.
If the deal is concluded soon, Mothatego will join two of his countrymen at Celtic, in forward Joel Mogorosi and defensive midfielder Mogogi Gabonamong.