Alese featured 21 times for Sunderland last season, but his campaign was cut short due to a thigh injury and the centre-back has yet to take part in a single match in the ongoing season as he is nursing himself back to fitness.
Sunderland signed Mayenda this summer from French side Sochaux to address their goalscoring issues, but the striker suffered a hamstring injury in a training session, which has left him out of action so far this season.
Mowbray revealed that both players have returned to the training ground, but stated that Mayenda and Alese will not be available for selection against Middlesbrough on Saturday.
The Sunderland boss added that both will need to play Under-21s games to get back to match fitness and sharpness.
“The pleasing thing for me is that Aji has been back on the training ground and Eliezer Mayenda is back on the training ground”, Mowbray said at a press conference.
“They are obviously not ready and need to play some 21s games.”
Sunderland will welcome Michael Carrick’s Middlesbrough, who are on a five-match unbeaten run, to the Stadium of Light on Saturday.
