Mdaki is back home in Daveyton looking for a new club, having made 11 league starts last term following his signing a year ago.
Mashego, whose future at the club is under discussion, joined the team in November 2016 on a 20-month contract after leaving Mamelodi Sundowns. The 35-year-old netted twice in seven league starts in 2016/17.
United manager Luthando Zibeko refused to give anything away when asked about Mashego's situation.
"Look we will release a statement about the players we are signing and those we are releasing," says Zibeko.
The Port Elizabeth-based outfit recently recruited Kurt Lentjies from Maritzburg United and are in talks with Ajax Cape Town to bring in fellow playmaker Mark Mayambela.