He completed his exile last week and is in the squad for tonight’s clash with Liverpool at Wrexham’s Racecourse Ground.

The former Everton and Liverpool full-back was initially banned for 18 months after failing a drugs test following Boro’s 0-0 UEFA Cup draw with Skoda Xanthi in Greece last September.

He has always protested his innocence, but although he succeeded in having his suspension reduced by a third on appeal to the Court of Arbitration for Sport, he has been unable to clear his name.

However, new boss Gareth Southgate invited his former team-mate to train with his squad and will now look at him in a competitive game for the first time as he decides whether or not to offer him a contract.

Southgate has already indicated his willingness to give Xavier a second chance if he feels he can do a job for him.

He said recently: “Abel has protested his innocence throughout this. He feels it is a situation which is more a case of negligence rather than trying to cheat.

“Whether he is innocent or guilty, he has had a year’s ban, he has served his time and myself and the club feel that people deserve the opportunity to rebuild their lives or rebuild their careers in a situation like that.”

Xavier continues to insist he did not knowingly take a banned substance, and is desperate for a chance to revive his career.

He said as he waited for his ban to end: “It has been very difficult for me while I have been away from football. But there are different ways to react and I have always looked for the positives.

“I have always believed I was innocent and that I would be back again playing football at a high level.

“I do not want to look back any more. I am only interested in the present, and the present is here.

“I am totally against the use of drugs in sport. I am against people taking drugs.

“In any walk of life, you have a right to be integrated back into society once you have completed a sentence.

“I have done that and now all I want to do is to play football again.”