The Valencian side currently sit in fourth, but have won only two of their last 10 league matches and were knocked out of the Copa del Rey in midweek by Valencia having already lost key midfielders Juanlu, Valdo and Jose Barkero to injury.
Del Horno told the club's website: "We need to forget about the cup and concentrate on the league. The cup didn't catch us at a good time, it was a heavy toll on the squad and we've got a lot of players out."
However, Del Horno is hoping Levante can improve in front of goal after two successive 0-0 draws at home.
"We've lacked penetration and direction going forward and we have to improve on these aspects," he said.
"We owe a lot to our fans, though, and we have to give everything to try and win the game."
Despite the injuries, there is some relief for the hosts as captain Sergio Ballesteros returns from suspension.
Getafe manager Luis Garcia meanwhile, will be returning to familiar surroundings after three years in charge at Levante between 2008 and 2011.
He told Marca: "I am going to a place where I was very happy. We achieved very important things there, above all promotion, which I still maintain great pride in, more than anything because of what it meant for the club.
"We are going there with the intention of winning but without forgetting that we are going to a team who are fourth. Right now they are a Champions League team and it is one of the most difficult matches between now and the end of the season."
Rafael Lopez will be out for about a month after suffering a muscle tear in last weekend's 2-1 win over Racing Santander and Pedro Leon is also unavailable as he suffered another setback on his return from injury.