The promoted Delfini appeared to have finally clicked following a rough introduction to life in Serie A, briefly squeezing their way up the standings with back-to-back wins.
But Stroppa's men would go on to lose their next two matches - against Lazio and Udinese - and the Lombardy-born tactician has gone back to the drawing board to work out what has gone wrong.
Following Sunday's defeat in Friuli, Stroppa told Gazzetta.it: "Unfortunately it's the fine margins that count.
"There's always a fine line, but everyone has to do their own job properly, otherwise we'll go nowhere fast.
"I'm happy enough with how we are expressing ourselves but there is something missing.
"When we should be taking our chances, we don't."
Any revival against Stefano Colantuono's men will come without the services of Juan Quintero, who has suffered a muscle injury.
Defender Alessandro Crescenzi remains sidelined, while Giuseppe Colucci fills in for veteran midfielder Manuele Blasi, who is suspended.
Atalanta ended a morale-sapping three-game losing streak with victory over Siena last weekend, and the fixture calendar has been somewhat kind to the Orobici as they face relegation candidates once again.
Colantuono told Gazzetta.it: "We knew that it would be a tricky game and we didn't have a great first half but, in front of a full stadium, we came alive after the break and managed to win."
Federico Peluso is unlikely to travel after catching a cold but fellow defenders Stefano Lucchini and Cristian Raimondi are back in training.
Gian Bellini, Davide Biondini and Michele Ferri are long-term absentees for the Bergamo outfit, who have not won away from home since claiming the spoils at AC Milan in September.
La Dea have never won at the Stadio Adriatico in a top-flight encounter, though, but they can take heart from the memory of their comfortable 3-0 Coppa Italia win back in 2006.