The Robins sold long-standing centre-back Zak Vyner in January to Wrexham while defender Jamie Knight-Lebel remains on loan at League Two Swindon.
Eile was signed on deadline day, from MLS side New York Red Bulls, but is new to the Championship and team style although has gone on to play every minute of the past five games.
Struber conceded that with the injuries it seems “smarter” to have brought another player in during the window and that he has been speaking to players about who is best suited to a more versatile role.
“I confronted players with a bit of a different task and I have to feel with players could close the gap for one or other game in the next few weeks,” he said.
“This is a really big time to show character, show a big mentality individually but also team-wise.
“It’s a tough time but we have to handle this time with a good mentality, a clear mindset and also a really big optimism.”
