Carroll is yet to hold down a regular starting spot in the centre of Tottenham's midfield, and has previously enjoyed loan spells at Leyton Orient, Derby County and QPR.
After 26 league appearances in QPR's promotion-winning campaign from the Championship in 2013-14, Carroll returned to White Hart Lane for this season, but did not feature in Spurs' 1-0 victory at West Ham on the opening weekend.
Carroll arrives at the Liberty Stadium as a boost to Garry Monk's midfield options, with Leon Britton and Jay Fulton both currently out injured with knee complaints.
The 22-year-old has five caps for the England Under-21 side, all of which came in the UEFA Under-21 European Championships qualifier.
Carroll arrived in south Wales on Friday, and will be available for the visit of Burnley in the Premier League on Saturday.
