Ghana forward Inaki Williams did not participate in Atletico Bilbao's training at the Lezama facilities on Tuesday.
Inaki, who featured at the 2022 World Cup in Qatar for the Black Stars is currently racing against time to be fit for the clash against Eldense.
On Thursday, Atletico Bilbao will face Eldense at the San Mames in Round 32 of the Copa del Rey, a game the Ghanaian forward could miss.
Inaki Williams, Raul Garcia and Ander Capa were all not involved in group training as they trained on the sidelines due to injury.
The trio may be a doubt for the game against Eldense on Thursday.
Fellow Ghanaian counterpart Nico Williams trained and is set to make the starting lineup against Eldense.
Inaki Williams will be hoping to recover on time to join the team for the game on Thursday.