Luka Modric did not report for Tottenham Hotspur's final training session before their tour of the United States and there is doubt over whether he will board the team flight to Los Angeles that departs on Saturday.

The Croatia midfielder is determined to leave the club and the manager, André Villas-Boas, has confirmed that he will be permitted to do so if an acceptable offer was to come in. Tottenham are holding out for as close to £40m as possible.

Modric has his heart set on a move to Real Madrid, who have so far offered €32m (£24.9m), with a further €8m in add-ons, making the total package potentially worth a little over £31m, which is not enough for Tottenham.

The Madrid president, Florentino Pérez, is confident that Modric will move to his club and he would have taken encouragement from the player's no-show at Spurs Lodge on Friday. Modric did not train on Thursday either, the first scheduled day of his pre-season, although he did turn up at Spurs Lodge. He did not stay for long, leaving while the squad went through their morning session. Tottenham declined to explain why Modric did not attend the training ground on Friday.

Madrid want Modric to agitate for the transfer which, they feel, might help to drive down the price. It got him nowhere last summer, though, when he was equally keen to leave Tottenham for Chelsea, who had offered a package worth £40m. Modric submitted a transfer request in an attempt to force the issue but Daniel Levy, the Tottenham chairman, was unmoved and the player was made to stay.

Levy's stance has softened. Last summer, he was clear that Modric was not for sale to anybody for any money, whereas now he accepts Modric has his price. If Modric does not travel to the United States, Madrid would interpret that as evidence of them winning the battle but to Levy, it would make no difference. He will demand that his asking price is met, regardless.

Levy wants cash only from Madrid, and is not interested in any players in part-exchange. Tottenham have been offered the defender Ricardo Carvalho and the midfielder Nuri Sahin, among others.

Villas-Boas's priority midfield target is João Moutinho of Porto, his former club, while he is close to agreeing the permanent transfer of the striker Emmanuel Adebayor from Manchester City. Adebayor spent last season on loan at White Hart Lane. It promises to be a busy transfer window at Tottenham, not least because Villas-Boas has to sell players to comply with the Premier League squad limit.

Tottenham play LA Galaxy in Los Angeles on Tuesday, Liverpool in Baltimore a week on Saturday and New York Red Bulls in New York on Tuesday week.