Hummels, out since March with an ankle injury, and Blaszczykowski, back after a groin problem, had missed the first leg 0-0 draw in Spain last week.
"At the moment it looks good for all of them and they are all with the team in the hotel," Klopp told reporters on Monday, saying Marco Reus and keeper Roman Weidenfeller had also overcome minor knocks.
It is unlikely, though, that Hummels or Blaszczykowski will start on Tuesday given their lack of match practice.
The Germans, looking for their first semi-final spot in 15 years, have been undefeated so far this season but are aware of a major battle ahead, Klopp said.
"We want to continue our voyage. We have a good chance but there are no guarantees," Klopp said. "Those who want to see quarantees in football should keep their eyes shut over 90 minutes tomorrow."
"Everything is ready for a good game tomorrow, including our opponents."
His young squad is in unchartered territory in this competition after losing at the group stage last season following the 1997 Europan champion's lengthy absence from the continent's premier club competition.
Malaga have reached the last eight in their debut season.
"No one in our team has been in a Champions League quarter-final and we want to continue in the competition," said defender Marcel Schmelzer, who played with a face mask in the first game due to a broken nose.
"I will decide tomorrow if I will use the mask again or not," the Germany international added.