Carlos Queiroz's men need to win against Safet Susic's eliminated side and rely on Nigeria losing to Argentina in Porto Alegre to have any chance of making the round of 16.
Iran employed a compact 4-5-1 for its previous two Group F games and, after picking up a point in their opener against Nigeria, were only denied a second successive 0-0 draw by a sensational last-minute strike from Argentina captain Lionel Messi.PHOTOS: USA vs. Portugal | U.S. fan reactions | Beautiful people in Brazil
Iran had looked the more likely scorers during the second half of its game with the Albiceleste in Belo Horizonte, with Queiroz boldly switching to what was effectively a 4-4-2 for the dying minutes, throwing on Alireza Jahan Bakhsh in support of Reza Ghoochannejhad.
Given Iran must defeat Bosnia and Herzegovina to have any chance of progressing to the second stage at the expense of Nigeria, which faces Argentina in its final fixture, the Portuguese coach will be considering starting Jahan Bakhsh, with Ashkan Dejagah the man most likely to make way.
Queiroz must also decide whether to continue with Masoud Shojaei on the right-hand side of midfield or recall the man who replaced him in Belo Horizonte, Khosro Heydari.
Bosnia-Herzegovina had arrived in Brazil with high hopes of progressing to the last 16 but, after opening with a 2-1 loss to Argentina, its qualification hopes were ended by a controversial 1-0 defeat against Nigeria.
Coach Safet Susic has already admitted that motivating his star men for the final fixture could be problematic, and there are now reports that certain members of his squad do not want to play in Salvador.
However, key duo Miralem Pjanic and Edin Dzeko are expected to start. The former did not train Monday, but he was purely being protected for the game at Arena Fonte Nova.
Vedad Ibisevic is looking to be reunited with Dzeko in attack, after being restricted to the role of substitute for Bosnia’s opening two games, but Susic is expected to persevere with the more pragmatic 4-5-1 he embraced after employing a dynamic but vulnerable 4-4-2 formation in qualifying.