Justin Kluivert will wear shirt number 34 for Roma in tribute to his former Ajax team-mate Abdelhak Nouri.
The Netherlands international completed his switch to the Serie A side from Ajax for €17.25million last month.
Nouri was left with permanent brain damage after experiencing heart failure during Ajax's friendly against Werder Bremen in July 2017.
And Kluivert announced on Saturday he will honour Nouri in his choice of shirt number at Roma.
"Why 34? Appie's number," Kluivert wrote on social media. "My prayers and shirt number for you, my friend-brother who taught me so much."
34 July 6, 2018
Last month, Ajax confirmed a review of the on-field treatment received by Nouri was "inadequate".
Managing director Edwin van der Sar said: "We recognise our responsibility and liability for the consequences of this."
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