Carlo Bonte, from Belgium, sells on 13 December 2017 a "Southern Netherlands, 17th century" Healing of the lame by Peter and John, estimated at 6,000 to 8,000 Euro.
RKD seemed to point in the same direction. But the work had too many more Baroque elements to be satisfyingly attributed to Spranger.
Copies normally aren't worth a lot, but this one is good. If (and it's a big if) the original of the work is lost, then it might be worth even more as the best representation left of it, but usually for every copy I can find online a lot of others are still unavailable or much harder to find. It should be worth around the estimate.
If, by chance, this turns out to be the original after all (which isn't impossible, Cigoli isn't the most perfect artist and often has weaker parts in his works), it should be worth 30,000 Euro instead (not because a name is worth more than an anonymous work, but because an original is worth more than a copy).