diff --git a/src/field/pokemon.ts b/src/field/pokemon.ts
index 91b57501371..2f918eaca2f 100644
--- a/src/field/pokemon.ts
+++ b/src/field/pokemon.ts
@@ -3524,7 +3524,6 @@ export default interface Pokemon {
 
 export class PlayerPokemon extends Pokemon {
   public compatibleTms: Moves[];
-  public usedTms: Moves[];
 
   constructor(scene: BattleScene, species: PokemonSpecies, level: integer, abilityIndex?: integer, formIndex?: integer, gender?: Gender, shiny?: boolean, variant?: Variant, ivs?: integer[], nature?: Nature, dataSource?: Pokemon | PokemonData) {
     super(scene, 106, 148, species, level, abilityIndex, formIndex, gender, shiny, variant, ivs, nature, dataSource);
@@ -3548,7 +3547,6 @@ export class PlayerPokemon extends Pokemon {
       }
     }
     this.generateCompatibleTms();
-    this.usedTms = [];
   }
 
   initBattleInfo(): void {
diff --git a/src/phases/learn-move-phase.ts b/src/phases/learn-move-phase.ts
index 201019e8860..26088f5b835 100644
--- a/src/phases/learn-move-phase.ts
+++ b/src/phases/learn-move-phase.ts
@@ -44,6 +44,9 @@ export class LearnMovePhase extends PlayerPartyMemberPokemonPhase {
     if (emptyMoveIndex > -1) {
       pokemon.setMove(emptyMoveIndex, this.moveId);
       if (this.fromTM) {
+        if (!pokemon.usedTMs) {
+          pokemon.usedTMs = [];
+        }
         pokemon.usedTMs.push(this.moveId);
       }
       initMoveAnim(this.scene, this.moveId).then(() => {
@@ -91,6 +94,9 @@ export class LearnMovePhase extends PlayerPartyMemberPokemonPhase {
                         this.scene.ui.showText(i18next.t("battle:learnMoveForgetSuccess", { pokemonName: getPokemonNameWithAffix(pokemon), moveName: pokemon.moveset[moveIndex]!.getName() }), null, () => { // TODO: is the bang correct?
                           this.scene.ui.showText(i18next.t("battle:learnMoveAnd"), null, () => {
                             if (this.fromTM) {
+                              if (!pokemon.usedTMs) {
+                                pokemon.usedTMs = [];
+                              }
                               pokemon.usedTMs.push(this.moveId);
                             }
                             pokemon.setMove(moveIndex, Moves.NONE);