The hiatus came at the worst possible time for Athletic as they were just beginning to find some form with consecutive wins over Paris St Germain and Real Sociedad.
The Basque derby win over Sociedad was particularly significant as it was Athletic's first in La Liga this season and saw Fernando Llorente make a welcome return to form to score only his second and third goals of the campaign.
Iraola wants his side to pick up where they left off on Monday.
"The match against Osasuna is important for us because we are still in desperate need for points and are in the bottom half of the league table," the 29-year-old defender said.
"We won away in the derby but we have still not won at home in the league and we have to make up the ground on the teams above us.
"We have an obligation to make it three wins out of three."
Fernando Amorebieta was the hero for Venezuela last week as he scored the only goal in the 1-0 win over Argentina in only his second game since opting to represent the country of his birth, and he is likely to retain his place in defence despite the return of Borja Ekiza from suspension.
Llorente missed training earlier in the week with a slight hamstring injury but should recover in time to start. Ander Herrera is also available after six weeks out with a meniscus injury but is expected to take a place on the bench.
Osasuna have good and bad news on the injury front ahead of their trip to Bilbao.
Centre-backs Roversio and Sergio have recovered from injury and have been included in Jose Luis Mendilibar's squad but Masoud Shojaei's return from a foot problem has again been delayed. The midfielder is expected to undergo surgery for a third time and could miss the rest of the season.