Golf's lawmakers are to look at players using aids to help them read the lie of putts on greens.
The move by the Royal and Ancient and the US Golf Association, aimed at speeding up play, has been backed by leading English players Luke Donald and Ian Poulter.
With players and caddies often consulting green reading books the game has seen play take longer.
In response to the move, Donald tweeted: "Totally agree. There is an art to green reading that is getting lost, just like judging the wind & this will help speed up play."
More common sense being used 👍🏻 And green reading books should be banned, they slow down play. Players and caddies have heads buried in them https://t.co/c7b8Bksxyr
— Ian Poulter (@IanJamesPoulter) May 1, 2017
The R&A and USGA issued a joint statement, which read: "The R&A and the USGA believe that a player's ability to read greens is an essential part of the skill of putting.
"Rule 14-3 limits the use of equipment and devices that might assist a player in their play, based on the principle that golf is a challenging game in which success should depend on the judgement, skills and abilities of the player.
"We are concerned about the rapid development of increasingly detailed materials that players are using to help with reading greens during a round.
"We are reviewing the use of these materials to assess whether any actions need to be taken to protect this important part of the game. We expect to address this matter further in the coming months."