The 2018 FA Youth Cup winners have joined up with manager Nigel Adkins and his squad until the end of the season as they try and survive relegation from League Two.
Mather was absent for three straight Under-21 games across November, December and January due to injury but has scored 3 times since his return which earned him a three-year contract with the club that will expire in the summer of 2027.
United created a flexi-loan system in 2023, which allows youngsters to gain senior experience whilst remaining involved in the day-to-day environment at Carrington. This is no different for the pair who will enjoy first-team football as well as world-class facilities to hone their skills.
Defender Jackson, who hails from Oldham, represents Scotland at youth level and was named on the bench for four first-team matches at the end of the 2023/24 campaign. This will be his first loan away from the club but as he is joined by Mather he will likely feel welcomed at the club.