Eduardo, who suffered a horrific leg injury last February in Arsenal's Premier League match at Birmingham, was left on the bench in their 0-0 draw at north London rivals Tottenham Hotspur on Sunday after playing several games for the reserves.
"Having spoken to (Arsenal manager) Arsene Wenger and seen their practice sessions, I am assured that Eduardo is in great shape and he will play a part in Bucharest although he will not start," Bilic told reporters on Monday.
"It could be a turning point in his quest to resurrect his career, as it's clear to both Wenger and me that he can no longer make progress from practice only.
"He now needs match fitness," said Bilic, who also named Robert Kovac as Croatia's new captain after his brother Niko retired from international football last month.
Bilic's assistant Aljosa Asanovic added: "We sorely missed Eduardo, especially in the Euro 2008 finals, hence his return will be a major boost in our bid to qualify for the 2010 World Cup finals in South Africa."
Croatia, who prevented England from qualifying for Euro 2008 by beating them twice, reached the quarter-finals in last year's tournament.
They are second in World Cup qualifying Group 6, five points behind England after suffering a 4-1 home drubbing by Fabio Capello's men in September.
Romania, struggling in Group 7, will miss injured striker Adrian Mutu after he pulled a thigh muscle in Fiorentina's 1-0 win over Italian Serie A rivals Lazio on Sunday, as well as unfit captain Cristian Chivu.
"We hope to have Mutu back soon and that his injury is not serious, unfortunately neither he nor Chivu can play," Romania coach Victor Piturca told a news conference.
"Chivu returned to action recently after a thigh injury and he is not at his highest level of play at the moment."
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