Rusyn, 26, joined Sunderland two years ago and has played in 32 matches.
The decision to loan Rusyn was made to ensure he gets regular playing time in his current stage of development.
Sunderland's sporting director, Kristjaan Speakman, stated that the team worked hard to find a suitable opportunity for Rusyn this season.
Rusyn remains under contract with Sunderland until 2027.