The midfielder has missed Liverpool's last four matches, two of which they have lost, due to a hamstring injury.
Liverpool host Atletico at Anfield on Wednesday needing to overturn a 1-0 deficit from the first leg to keep their hopes alive of successfully defending their Champions Legaue title.
Goalkeeper Alisson will still be absent after missing Saturday's win against Bournemouth with a hip injury, but Klopp confirmed Henderson is available again:
Atleti have not enjoyed the best 2019-20 campaign and are in fifth in La Liga.
However, they put in a vintage display in last month's first leg to edge their noses in front in the tie:
A similarly immaculate performance will be needed from Diego Simeone's side if they are to convert that lead into a quarter-final spot after Wednesday's second leg.
Klopp is acutely aware of the threat posed by the Spanish side and praised the talent of 20-year-old Joao Felix, who has scored twice in three league games since his return from injury:
The German manager added that his team will feed off the Anfield crowd in a bid to turn the tie around:
The 2019-20 campaign is already set to go down in Liverpool history because the Reds will almost certainly end their 30-year wait for a 19th English league title.
There is the potential, though, that the Reds' extraordinary season could end with a slight whimper if they make a premature exit from the Champions League.
That should motivate them more than ever to stay on track in the Champions League as they look to join AC Milan on seven titles.