That is according to Fabrizio Romano, who states that the agreement includes striker Viktor Gyokeres.
New United boss Ruben Amorim also made this clear when he left Sporting, stating there would be no January transfers between the clubs.
Romano stated this week: "In the discussions between Sporting and Man United when they agreed on Amorim's exit in November, there was also a gentleman’s agreement for United not to bring in any Sporting player in January.
"This is because Sporting hope to win the title this season and they don't want to lose any other part of the squad in January, after having the big shock of Ruben Amorim leaving in the middle of the season.
“My expectation is for Manchester United to eventually look at Sporting players in the summer, if Amorim approves; not in January."
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