Morrison played the final eight minutes in place of Ogenyi Onazi in a 3–0 loss (3–1 on aggregate). Four days later, he made his Serie A debut in a 4–0 loss to Chievo, coming on at half time in place of Senad Lulić. Morrison featured scarcely in Lazio's start to the 2015–16 season, with coach Stefano Pioli criticising his effort and inability to speak Italian. In October 2015, he posted a message on Twitter saying solely "January..", leading to more reports of an exit from the club. On 31 January 2017, Morrison returned to Queens Park Rangers on loan until the end of the 2016–17 season. He made five appearances for them in the Championship, all but one as a substitute, and the West London club did not take the option to sign him for £2 million. On 31 August 2017, Morrison joined Atlas on loan until the end of the 2017–18 season. Only one other Englishman had previously played in Liga MX, Chester-born Antonio Pedroza, who was raised in Mexico and whose father is Mexican. In February 2019, having returned to Lazio in the previous July, Morrison trained with Allsvenskan side Östersund at their pre-season camp in Marbella. On 14 February, it was confirmed that he had signed a six-month contract with the club. He scored his first goal for the club on 3 March 2019, in a Svenska Cupen match against IK Sirius, the first goal of a 3–0 win. In June 2019, Morrison's contract was not renewed due to frequent injury and his salary, despite the manager's praise of him. In July 2019, manager Chris Wilder confirmed that Morrison had begun training with newly promoted Premier League side Sheffield United ahead of the new season, describing the move as being "a good fit for the player and the club". On 16 July, it was confirmed that Morrison had signed a one-year deal. On 31 January 2020, Morrison signed for Middlesbrough, on loan for the remainder of the 2019–20 season. Morrison has been capped by England at under-16, under-17, under-18 and under-21 levels. Morrison is also eligible to play for Jamaica and, in November 2012, he was reported to be considering representing them at international level. He made his England under-21 debut on 10 October 2013, in a 4–0 away win against San Marino.