The midfielder has been struggling to secure regular first team action at Los Che, but is determined to grab his chance with one of his rivals out due to injury
The Argentine underwent surgery earlier this week, and will be out of action for the remainder of the season.
Parejo, who joined Valencia from Getafe in the summer of 2011, feels sympathy for his team-mate, but insists that he will give his all to convince head coach Unai Emery of his abilities.
"Up until now I have not had many opportunities," the 22-year-old was quoted as saying on the Uefa website.
"While it's awful what happened to Ever, it's obvious I might have more chances now and I'm going to try and take them. In fact, I'll give everything I've got."
The former Getafe star then looked back at his side's Europa League round of 32 win over Stoke City, and was very pleased with Valencia's progress.
"We're content with how we played because getting the win and qualifying wasn't easy. This comes after an awful weekend [when Valencia lost 5-1 to FC Barcelona] and with our morale on the floor, so this win is very welcome indeed."
Valencia will now have to deal with Eredivisie giants PSV in the round of 16. The first leg takes place at Mestalla on March 8.