The batsman admitted interfering with the ball with a mint sweet while playing for Warwickshire in a Second XI Championship clash with Glamorgan in Cardiff earlier this month.
England and Wales Cricket Board (ECB) disciplinary officials said they had taken a lenient stance because Coleman had committed the offence with the full knowledge of team captain Paul Best.
Former Grange player Coleman, 21, received a fortnight’s ban, suspended for two years.
Play was halted when senior umpire Martin Saggers spotted Coleman sucking a Murray Mint before using his saliva to put a shine on the ball. Saggers quizzed Best and then summoned squad coach Tony Frost.
In spite of only handing out an admonition, an ECB spokesman said: “We wish to make clear that any attempt to alter the natural condition of the ball using an artificial substance will be taken very seriously. The panel took into account that Mr Coleman pleaded guilty, that he is a young player and that he was allowed to act in this way with the knowledge of his captain.
“Should he commit any further breach of any ECB rules, regulations or directives during the two year period, then at the discretion of the Cricket Discipline Commission, this penalty will take effect.
“The panel also wish to make it clear that the personal circumstances of Mr Coleman were taken into account and that the sanction is not to be seen as setting a precedent in any future cases of this kind.”
Warwickshire were fined £5,000 and were stripped of all their points earned in the defeat, while Coleman received three penalty points. This sanction will also remain on his record for two years.