diff --git a/tsdb/index.go b/tsdb/index.go
index d85d15c289..1acfbbf8a3 100644
--- a/tsdb/index.go
+++ b/tsdb/index.go
@@ -35,6 +35,9 @@ type Index interface {
 	DropSeries(seriesID uint64, key []byte, cascade bool) error
 	DropMeasurementIfSeriesNotExist(name []byte) error
 
+	// Used to clean up series in inmem index that were dropped with a shard.
+	DropSeriesGlobal(key []byte) error
+
 	MeasurementsSketches() (estimator.Sketch, estimator.Sketch, error)
 	SeriesN() int64
 	SeriesSketches() (estimator.Sketch, estimator.Sketch, error)
diff --git a/tsdb/index/tsi1/index.go b/tsdb/index/tsi1/index.go
index 64a290a046..6459cb1753 100644
--- a/tsdb/index/tsi1/index.go
+++ b/tsdb/index/tsi1/index.go
@@ -643,6 +643,9 @@ func (i *Index) DropSeries(seriesID uint64, key []byte, cascade bool) error {
 	return nil
 }
 
+// DropSeriesGlobal is a no-op on the tsi1 index.
+func (i *Index) DropSeriesGlobal(key []byte) error { return nil }
+
 // DropMeasurementIfSeriesNotExist drops a measurement only if there are no more
 // series for the measurment.
 func (i *Index) DropMeasurementIfSeriesNotExist(name []byte) error {