Cahill, a veteran of 33 matches for the Socceroos, has been in pre-season training with his Major League Soccer club - New York Red Bulls - but was overlooked for the match.
Middlesbrough defender Rhys Williams is back in the national team setup after a protracted run of injuries, where he'll be joined by three other players returning to the squad: Jason Davidson, Adam Federici and Michael Zullo.
Korea Republic-based defender Robert Cornthwaite kept his place, after his surprise selection as an injury replacement player for Australia's EAFF East Asian Cup qualifying campaign in December, 2011.
Osieck explained his decision not to select any A-League-based players in the squad.
'I had a good look at the Australian-based and Asian-based players in Korea Republic and Hong Kong at EAFF East Asian Cup Qualifiers so this is a good opportunity for me to check the performance of the European-based players that I haven’t seen since last October," he said.
'Over the past week or so, I have also been scouting a number of players throughout Europe, so I have a good idea on where they are currently at, but being in camp will give me a much better idea.
'One player who was definitely in contention for selection was Adam Sarota, but unfortunately a recent serious knee injury has ruled him out. We wish Adam a safe and speedy recovery and hope to see him on the field soon enough.
'In terms of Romania, it’s no secret that they are a quality team, well placed in their qualification group and they play good football.
'It’s always good to test ourselves against tough opposition and Romania will be a good yard-stick for us in the lead up to our game against Oman in March,"
This will be the first meeting between the 36th-ranked Australia and 33rd-ranked Romania at senior men's international level.
The Socceroos are in second position of Group B of the 2014 FIFA World Cup Asian qualifiers with a win against Iraq (2-1), draws against Oman (0-0) and Japan (1-1) and a loss to Jordan (1-2) at the half way point of the final round.
Romania is placed third position of Group D in its 2014 FIFA World Cup European qualifiers after four matches.
Romania v Australia, Thursday 7 February, 7am (AEDT) Estadio Ciudad de Malaga, Spain
Socceroos squad to play Romania:
Mark BRESCIANO Al Gharafa, Qatar; Alex BROSQUE Al-Ain Club, UAE; Robert CORNTHWAITE Chunnam Dragons, Korea Republic; Jason DAVIDSON SC Heracles Almelo, Netherlands; Adam FEDERICI Reading FC, England; James HOLLAND FK Austria Vienna, Austria; Brett HOLMAN Aston Villa FC, England; Mile JEDINAK Crystal Palace FC, England; Robbie KRUSE Fortuna Dusseldorf, Germany; Mathew LECKIE FSV Frankfurt 1899, Germany; Ryan McGOWAN Shandong Luneng Taishan FC; Matt McKAY Changchun Yatai FC, China PR; Lucas NEILL Al-Wasl Sports Club, UAE; Tommy OAR FC Utrecht, Netherlands; Nikita RUKAVYTSYA FSV Mainz, Germany; Mark SCHWARZER Fulham FC, England; Luke WILKSHIRE FK Dinamo Moscow, Russia; Rhys WILLIAMS Middlesbrough FC, England; Michael ZULLO FC Utrecht, Netherlands.