Rob Edwards is still technically at the Riverside helm, although is widely expected to vacate his post to join Wolverhampton Wanderers.
Permission for talks was granted over the weekend, but Middlesbrough have made their disappointment with the development clear.
Edwards was stood down at the weekend, with his assistant Adi Viveash stepping in to oversee a 2-1 win over Birmingham City.
Viveash was asked about his own potential interest in the head coach role, but remained coy and lavished praise on the players.
Former Huddersfield Town boss and ex-Leeds United coach Carlos Corberan was an early favourite for the role, with his Valencia side struggling in La Liga.
However, he has now been overtaken by a new frontrunner in the BetVictor odds, which also feature some new names.
Here is a fresh look at the favourites to replace Edwards as Middlesbrough boss.
