The full-back is highly-rated, having been capped by Brazil's under-20 and under-23 levels but has yet to be given his senior cap.
Wendell managed to make 30 appearances in all competitions for the Bundesliga outfit last season, scoring three times and providing the same number of assists.
The 24 year-old full-back has turned out over 100 times for his current team, and would be a qualified replacement to Everton veteran Leighton Baines, who has spent 10 seasons with the Toffees.
Marco Silva has said that he wants to balance his squad more, which disappointed last season following spending big in the attacking and midfield areas, particularly on the signing of Gylfi Sigurdsson from Swansea for £40million.