Inter Milan sporting director Piero Ausilio says Eder was a transfer request from coach Roberto Mancini.
Ausilio admits they also searched for a midfielder.
“We could only get one player. At the beginning we wanted to get a midfielder, but there wasn't the quality out there that you'd think.
“In terms of cost and quality, we didn't find anyone who could do the job.
“You can play in a lot of different ways in football, so we evaluated everything with the Coach [Mancini] and decided the right thing to do was get someone for the attack.
“Eder is different from the other players in our squad, our attacking department is one of the best and all our strikers have different characteristics.
“The former Sampdoria man has completed our transfer campaign, then we couldn't get a midfielder so we took [Assane] Gnoukouri off the market.
“He did well last year, he's an asset to us. Mancini admires him and we think that with him our midfield is complete."