The future of Atletico Madrid striker Radamel Falcao is again shrouded in mystery. Botoga sources say Manchester United and Chelsea have joined the battle for the Colombia international this week.

And El Colombiano says its emerged that as part of Atletico's friendly with Nacional a clause is included which sees Falcao not obligated to take part in the glamour fixture.

It's understood the clause has been included in the hypothetical case that Falcao needs to be free to negotiate with interested clubs.