In 2018 and earlier years, Rule 16-1c allowed players only the ability to repair old hole plugs and ball marks, but forbid the repair of other damage including spike marks, hoof prints from deer, and other imperfections.

In 2019, these rules have been relaxed. In 2019, Rule 13.1c(2) allows for repair of almost any damage to the putting green. “Damage on the putting green” will be defined to include all types of damage — ball marks, shoe damage (spike marks, heel prints), indentations from the dope who dropped the flagstick from chest height, animal damage, etc. — except aeration holes, natural surface imperfections, and natural wear of the hole.

These repairs can be done with the player’s hand, foot, or other part of the body, or a ball mark repair tool, tee, club, or similar item of normal equipment and cannot unreasonably delay play. In other words, no tapping down 200 spike marks, nor can you bring out a green roller. 🙂

The reasons for this? The USGA and R&A point out that a putting green is specially prepared for rolling the ball along the ground, so the players rights or privileges should account for that, and allow them to do things they wouldn’t be able to do elsewhere, including:

  • The player may mark, lift and clean a ball on the green at any time, remove sand and loose soil on the green, and repair old hole plugs and ball marks. So, given this philosophy of allowing players to try to have a smooth surface for rolling the ball, there is no conceptual reason for prohibiting repair of other types of damage (whether made by players, animals, maintenance staff, etc.).
  • This Rule change will eliminate the frequent questions among players and referees about whether a particular area of damage on the green is a ball-mark that may be repaired or is a shoe mark or other damage that must not be repaired. This simplifies things – virtually all “damage” may be repaired.
  • This change will also reduce the request that players care for the course by repairing damage… but only after they’ve finished  putting out. (See Decisions 1-2/0.7 and 1-2/3.5 in the 2018 Rules of Golf).
  • The concern has been noted that allowing repair of all damage on the putting green could slow down play if players try to repair too much, but the USGA and R&A believe that it’s unlikely for most players and that the Rule against unreasonable delay (as well as a Committee’s pace of play policy) can be used to address situations where a player seeks to make excessive repairs.

https://www.youtube.com/watch?v=Frk6UR2LPvg