Manchester United manager David Moyes attended the Bundesliga game between Borussia Monchengladbach and Bayern Munich on Friday.
The Scot, who was at the game along with coaches Phil Neville and Steve Round, sat next to Toni Kroos's agent, Sascha Breese from the Sports Total agency, at Borussia-Park.
According to the Daily Mail, Moyes was at the match to watch Bayern striker Mario Mandzukic and Moenchengladbach midfielder Patrick Herrmann, but he could now make a summer bid for Kroos after being informed that the 24-year-old could be available.
Kroos's talks with Bayern over renewing his contract, which runs out in June 2015, have stalled and Moyes could take advantage of the situation at the end of the season.
However, Kroos is considered as one of coach Pep Guardiola's most important players and United could have to pay at least £25m to sign the Germany international, if Bayern do decide to sell him.