Manchester United have been put on alert as Toni Kroos' future at Bayern Munich appears to be in doubt following comments from Pep Guardiola.
Kroos had earlier this week alerted United by refusing to rule out a move away from Bayern, and United boss David Moyes was in Germany last week to watch Kroos in action for the Bundesliga giants and is understood to have met one of the Germany international's representatives.
The 24-year-old, who is out of contract at the end of next season, appeared to be unhappy when substituted after just an hour of Bayern's last game.
Guardiola's side were losing 1-0 to Stuttgart but fought back to win 2-1, and speaking after the game, the Spaniard said of Kroos: "He is an important player but things can move fast in football.
"Here today, gone tomorrow."
Bookmakers believe a move to Old Trafford could be on the cards before the January transfer window closes, with Sky Bet making Moyes' side 4/9 favourites to sign Kroos in their Toni Kroos Club After January Transfer Window market, ahead of Chelsea at 4/1.
The transfer window closes on Friday night at 23:00 GMT.