Tottenham Hotspur have been banned from tweeting their line-up alongside promotions for betting firm William Hill if players aged under 25 are involved by the UK's advertising regulator.
For Champions League clashes, Spurs announce their starting XI and include a link to the bookmaker's website, offering their 3.4million followers the 'latest odds' on the game.
The Advertising Standards Authority (ASA) investigated a tweet on March 5, ahead of Tottenham's away win over Borussia Dortmund, and found it was 'irresponsible' and breached gambling rules.
That line-up featured two young players in Davinson Sanchez, 22, and Harry Winks, 23. It was retweeted close to 1,000 times and liked by 3,600.
Tottenham and William Hill argued Sanchez and Winks were not the 'sole focus of the advert' and that they were only included because they were in the line-up.
The ASA dismissed the response and said: 'The ad must not appear again in the form complained of.'
Promotions for betting companies in football has become a controversial issue for the way it has engulfed the English game. It has led to a clampdown amid fears it could appeal to children.
On Tottenham, the ASA added: 'We understood the intention of the tweet was to inform the audience of the starting line-up.
'However, we considered that of equal measure was its aim to offer the audience an opportunity to place a bet on the match.
'In that context, while the significance of Harry Winks and Davison Sanchez was no greater than the other players in the line-up, the 11 players were the focus of the tweet, and we considered that each of them played an equally significant role in the marketing communication.
'The ad had not appeared in a place, such as William Hill's own website, where a bet could be placed through a transactional facility, nor had the two players been used to illustrate specific betting selections where they were the subject of the bet offered.
'In light of the above, we concluded that the ad was irresponsible and therefore breached the code.'