The 24-year-old arrives at the County Ground having struggled for first-team opportunities at Leeds this term, spending three months on loan at Carlisle where he scored three times in 11 appearances before his return to Elland Road in mid-January.
Speaking on the move, Leeds manager Simon Grayson told the club's official website: "Mike has found opportunities limited this season.
"He got some games in at Carlisle which did him good and we see this as another opportunity for him to play regular football."
Robins boss Danny Wilson has moved to bring in cover for January signing Elliot Benyon and fellow forward Thomas Dossevi, who both limped off in last weekend's defeat to Carlisle, although the pair are not expected to be long-term absentees.
The American goes straight into Town's squad for Saturday's trip to Southampton.