diff --git a/tsdb/ooo_head.go b/tsdb/ooo_head.go
index bbb0f10e77..f9746c4c61 100644
--- a/tsdb/ooo_head.go
+++ b/tsdb/ooo_head.go
@@ -40,7 +40,8 @@ func (o *OOOChunk) Insert(t int64, v float64, h *histogram.Histogram, fh *histog
 	// try to append at the end first if the new timestamp is higher than the
 	// last known timestamp.
 	if len(o.samples) == 0 || t > o.samples[len(o.samples)-1].t {
-		o.samples = append(o.samples, sample{t, v, h, fh})
+		// TODO(krajorama): pass ST.
+		o.samples = append(o.samples, sample{0, t, v, h, fh})
 		return true
 	}
 
@@ -49,7 +50,8 @@ func (o *OOOChunk) Insert(t int64, v float64, h *histogram.Histogram, fh *histog
 
 	if i >= len(o.samples) {
 		// none found. append it at the end
-		o.samples = append(o.samples, sample{t, v, h, fh})
+		// TODO(krajorama): pass ST.
+		o.samples = append(o.samples, sample{0, t, v, h, fh})
 		return true
 	}
 
@@ -61,7 +63,8 @@ func (o *OOOChunk) Insert(t int64, v float64, h *histogram.Histogram, fh *histog
 	// Expand length by 1 to make room. use a zero sample, we will overwrite it anyway.
 	o.samples = append(o.samples, sample{})
 	copy(o.samples[i+1:], o.samples[i:])
-	o.samples[i] = sample{t, v, h, fh}
+	// TODO(krajorama): pass ST.
+	o.samples[i] = sample{0, t, v, h, fh}
 
 	return true
 }