Manchester United boss Michael Carrick's side have not ruled out completing the departure of Joshua Zirkzee, who remains a target for Juventus, and are keeping other options open at centre-forward, with Matanovic emerging as one name under consideration.
According to journalist Ekrem Konur, United have carried out preliminary checks on the 23-year-old, whose performances in the Bundesliga have made him a wanted man elsewhere in the Premier League too.
Tottenham Hotspur are also seriously exploring a move for the forward, the same source reports. SC Freiburg's asking price for Matanovic remains unclear for now, but the Croatia international has sparked a tug-of-war between Spurs and United as both clubs weigh up their options up front before the market shuts.
Matanovic, who stands at 1.94 metres and has drawn comparisons to United's own Benjamin Sesko for his physical profile, joined Freiburg from Eintracht Frankfurt last summer after struggling for game time in Frankfurt, and scored 11 goals from just 14 Bundesliga starts last season.
Born in Hamburg and developed at St Pauli, he represents Croatia at international level despite coming through the German youth system, and his aerial ability and hold-up play have made him an increasingly attractive target as clubs across the Premier League search for reinforcements up front.
Eintracht Frankfurt are reported to have negotiated a 15 percent sell-on clause when they sold him to Freiburg, meaning the Bundesliga club would also stand to benefit from any transfer to England.