In professional team sports, tapping up (British English) or tampering (American English) is an attempt to persuade a player contracted to one team to transfer to another team, without the knowledge or permission of the player's current team. This kind of approach is often made through the player's agent. It is expressly forbidden in many professional leagues, but is not illegal.
A milder form of "tapping up" involves a manager's letting his admiration for a player at another club become known, perhaps by hinting at his interest while working as a pundit during the broadcast of a game in which the player is taking part, "he's the sort of player any manager would be very keen to sign", or by lavishing praise in programme notes when the two teams meet. There are also the "source close to the manager"-type newspaper rumours which in many case originate within the club and are intended to flag an interest while retaining plausible deniability against charges of tapping up. Most ex-players candidly admit that tapping up has gone on in football for decades. Nottingham Forest manager Brian Clough later said, "we tapped more players than the Severn-Trent water board!"
Notorious examples of tapping up in the Premier League include Dwight Yorke, Jermain Defoe and Ashley Cole. In these cases, the incidents soured the relationship between the player and his original club. Cole was found guilty and fined £100,000 by the Premier League on 2 June 2005 for a meeting in a hotel in January 2005 between himself, the Chelsea manager José Mourinho, Chelsea chief executive, Peter Kenyon, and his agent Jonathan Barnett.