The situation has developed following a difficult period for the two attacking players, with their futures now being considered as Napoli assess how best to reshape the squad during the winter market.
Lucca's position appears the more pressing. The Italian striker has struggled to establish himself in Massimiliano Allegri's team, making 10 Serie A appearances but starting only twice. He has accumulated 285 minutes in the league without scoring.
The former Udinese forward has therefore found it difficult to justify a regular place in the side, and Napoli are understood to be considering another departure just months after bringing him into the squad.
A loan is regarded as a more realistic possibility than a permanent sale. Napoli invested €35 million in Lucca two summers ago and would be reluctant to accept a deal that significantly reduced the value of that investment.
A temporary move could give the 25-year-old an opportunity to regain confidence and regular playing time, while allowing Napoli to reassess his position at the end of the season.
Udinese have emerged as one possible destination, potentially offering Lucca the opportunity to return to a club where he previously made an impression. Torino have also been mentioned as a possible option, with the possibility of a renewed interest in the striker.
Lang's situation is different, but the Dutch winger has also come under pressure after an inconsistent spell since returning to Napoli from his loan at Galatasaray.
The latest tension followed Napoli's match against Lazio, when Lang became involved in an uncomfortable exchange with supporters. His relationship with sections of the fanbase has reportedly deteriorated, raising the possibility that the club could consider offers when the transfer window opens.
The winger had already attracted interest during the summer, with both Ajax and Galatasaray exploring the possibility of a move. Neither club managed to complete an agreement, and Lang remained at Napoli.
However, the club may now have to decide whether to continue backing the player or use his departure to create space for another attacking signing.
The situation has been further complicated by the scrutiny surrounding Lucca, who was also involved in a reported disagreement with team-mate Kevin De Bruyne during Napoli's away trip to Porto.
The two cases have added to the pressure on the club's attacking options, with Napoli needing to determine whether changes are required to improve the balance of the squad.
At least one of the players could leave Castel Volturno in January, according to Tuttomercatoweb. The coming weeks will be important in establishing whether concrete offers arrive and whether the club believes either departure would help its plans.
Lucca's lack of minutes and goals makes a temporary move an understandable option, while Lang's uncertain relationship with supporters could make a fresh start attractive to all parties.
Napoli now face a decision over two players who arrived with expectations of making an impact but have yet to establish themselves as consistent contributors.