The Pamplona outfit have picked up eight points from their last five matches to boost their survival hopes but they are still 17th in the standings and just two points above the drop zone.
However, they will be looking to improve their lot on Saturday when they play host to a struggling Zaragoza side who are just two points better off and who have won just one of their nine league and cup matches in 2013.
Arribas admits it is a potentially crucial fixture for his side, telling reporters: "It is one of the most important games of the season. They are a direct rival and, if we beat them, we will climb above them.
"I think that survival will be decided by the points that we pick up at home, because we face a number of our main rivals at home."
Osasuna coach Jose Luis Mendilibar is without injured goalkeeper Asier Riesgo while midfielder Anthony Annan is still absent following his African Nations Cup campaign with Ghana.
Zaragoza make the short trip to Pamplona without a league victory since December and having not picked up a three-point haul at Osasuna since 2003.
They have also failed to even score on their last four visits to the Reyno de Navarra, but goalkeeper Roberto Jimenez is hoping for better on Saturday.
He said: "It's a very important game for us, due to the rivalry that there is, the time since we've won at this ground and the situation of the team.
"With all that in mind Saturday is a good day to get back to winning ways."
He added: "We know what this match means to the Zaragoza fans and it's an added motivation for us."
Coach Manuel Jimenez is without midfielder Ndri Romaric due to a calf injury.