Grim Strider

• WWizards of the Coast2017-04-18
  Official Ruling
  If a spell or ability causes you to draw cards and then has you remove some from hand (such as by discarding them or putting them on top of your library), Grim Strider may briefly have 0 toughness or less. As long as its toughness is 1 or greater again after the spell or ability is finished resolving, it will remain on the battlefield.
• WWizards of the Coast2017-04-18
  Official Ruling
  Because damage remains marked on a creature until it’s removed as the turn ends, the damage a Grim Strider takes during combat may become lethal if you draw cards later in the turn.

Rulings via Scryfall