Championship outfit Cardiff were linked with a move for the 21-year-old during the summer transfer window, but the switch never materialised.
However, rumours resurfaced recently that the Bluebirds had reignited their interest in the former Manchester United trainee, who has made two appearance for the Hammers this season.
Despite the fact that there has been no official confirmation from either club, Morrison took to Twitter this afternoon to reveal that an agreement has been reached, which will see him spend the next three months at the Cardiff City Stadium.
happy to get a 3 month loan @CardiffCityFC time to start playing some football again 😊⚽️— ra'vel (@morrisonravel) September 23, 2014
Morrison, who spent part of last season on loan with Queens Park Rangers, joined West Ham from Man United in January 2012, although his stint at Upton Park has been blighted by a number of off-field issues.