Fourth-placed Dortmund will start the second half of the Bundesliga season next week 12 points behind leaders and reigning champions Bayern Munich.
With Ilkay Gündogan (back), Mats Hummels (foot) and Marcel Schmelzer (calf) all close to playing again, Klopp believes Dortmund will have the depth required to challenge for titles in the DFB Pokal and UEFA Champions League.
Klopp said his team's poor first half of the season, where they claimed 10 wins and two draws from 17 games, was understandable, considering the players that were missing.
"I can occasionally be very critical of my players but they weren't to blame for many things that happened (during the first half of the season). We lost the entire spine of our team," Klopp told RuhrNachrichten.de.
"I can't blame the players for a lack of effort. We just want to prepare well so all the BVB (Dortmund) fans can look back on the season with a smile."
While the Bundesliga title seemingly out of reach, Klopp has claimed a second-place finish would make him 'really happy' in the German league.
The 46-year-old coach added there is no reason why Dortmund could not challenge for silverware in the Champions League, where they reached the final last season, or the DFB Pokal.
"We haven't set ourselves a limit in the DFB Pokal, we naturally want to get as far as possible in that competition," Klopp said.
"We're not favourites in the Champions League but we don't want to set ourselves a specific target there either. Our aim is simply to prepare the team for the challenges ahead."
