diff --git a/chromecast/starboard/media/renderer/starboard_renderer.cc b/chromecast/starboard/media/renderer/starboard_renderer.cc
index f456c8b6f26b4..5450bccd27d3c 100644
--- a/chromecast/starboard/media/renderer/starboard_renderer.cc
+++ b/chromecast/starboard/media/renderer/starboard_renderer.cc
@@ -61,11 +61,14 @@ void StarboardRenderer::Initialize(::media::MediaResource* media_resource,
   ::media::DemuxerStream* video_stream =
       media_resource->GetFirstStream(::media::DemuxerStream::Type::VIDEO);
 
-  player_manager_ = StarboardPlayerManager::Create(
+  // Create into a local first so a failed Create() does not destroy the
+  // existing player_manager_ (and the SbPlayer that
+  // geometry_change_handler_.sb_player_ still references).
+  auto new_player_manager = StarboardPlayerManager::Create(
       starboard_.get(), audio_stream, video_stream, client,
       cast_metrics_helper_, media_task_runner_, enable_buffering_);
 
-  if (!player_manager_) {
+  if (!new_player_manager) {
     LOG(ERROR) << "Unable to create StarboardPlayerManager";
     media_task_runner_->PostTask(
         FROM_HERE,
@@ -74,6 +77,10 @@ void StarboardRenderer::Initialize(::media::MediaResource* media_resource,
     return;
   }
 
+  player_manager_ = std::move(new_player_manager);
+  // Same-sequence: OnVideoGeometryChange cannot interleave between the
+  // move-assign above (which destroys the old SbPlayer) and the SetSbPlayer
+  // below, so sb_player_ is never observed dangling.
   geometry_change_handler_.SetSbPlayer(player_manager_->GetSbPlayer());
 
   if (pending_volume_.has_value()) {
diff --git a/media/mojo/services/mojo_renderer_service.cc b/media/mojo/services/mojo_renderer_service.cc
index f10c330b74968..6c44ecb186102 100644
--- a/media/mojo/services/mojo_renderer_service.cc
+++ b/media/mojo/services/mojo_renderer_service.cc
@@ -58,7 +58,9 @@ void MojoRendererService::Initialize(
         streams,
     InitializeCallback callback) {
   DVLOG(1) << __func__;
-  DCHECK_EQ(state_, STATE_UNINITIALIZED);
+  // A compromised renderer can call Initialize() repeatedly; downstream
+  // ::media::Renderer impls do not expect re-init. Enforce in release.
+  CHECK_EQ(state_, STATE_UNINITIALIZED);
 
   client_.Bind(std::move(client));
   state_ = STATE_INITIALIZING;