The former Preston, Birmingham City, and Leicester defender had been in the US for just four months, having been released by Ipswich Town last December without playing a game for the club.
After a period without a club, the defender sought a fresh start alongside Brazilian star Kaka at Orlando, who are making a first appearance in the MLS Eastern Conference.
Prior to Saturday’s announcement, St Ledger had started 14 matches for the club, including 12 in succession.
Now 30, the defender has endured a controversial career in the game, suffering a series of fall-outs with managers such as Barry Fry, Gordon Strachan, and Alan Irvine, and now appears to have fallen foul of Orlandomanager Adrian Heath, the former Everton striker.
St Ledger has played 37 times for Ireland and was a regular under Giovanni Trapattoni, but has not featured under Martin O’Neill.
Orlando refused to comment further on St Ledger’s alleged indiscipline, but the player didn’t feature in Saturday’s 5-2 win over Columbus Crew.
On Wednesday, City announced the capture of Real Madrid academy defender David Mateos.