Napoli added Manolo Gabbiadini to their Europa League list, but Ivan Strinic and Michu miss out.
The updated squad was handed in to UEFA today following the close of the January transfer window.
Ex-Sampdoria striker Gabbiadini is a new addition, replacing Michu, but injured Lorenzo Insigne remains.
That is because Insigne is the only player who qualifies as a youth product from this club.
It also means Rafa Benitez only has 22 players in his squad rather than 25.
Another mid-season signing Strinic cannot take part as he already played in this competition with Dnipro.
Napoli will face Trabzonspor in the Round of 32, playing in Turkey on February 16 and at the Stadio San Paolo on February 26.
Napoli UEFA squad list: Rafael , Andujar; Maggio, Henrique, Britos, Zuniga, Koulibaly, Ghoulam, Albiol, Mesto; De Guzman, Jorginho, David Lopez, Gargano, Inler; Callejon, Higuain, Mertens, Hamsik, Gabbiadini, Insigne, Duvan Zapata