diff --git a/pkg/controller/perconaservermongodb/mgo.go b/pkg/controller/perconaservermongodb/mgo.go
index 9905c4d4d..e9c5d032b 100644
--- a/pkg/controller/perconaservermongodb/mgo.go
+++ b/pkg/controller/perconaservermongodb/mgo.go
@@ -17,6 +17,7 @@ import (
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/utils/ptr"
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
 
 	api "github.com/percona/percona-server-mongodb-operator/pkg/apis/psmdb/v1"
@@ -177,58 +178,62 @@ func (r *ReconcilePerconaServerMongoDB) reconcileCluster(ctx context.Context, cr
 	}
 
 	if cr.Spec.Sharding.Enabled &&
+		cr.Spec.Sharding.Mongos.Size > 0 &&
 		!rstRunning &&
-		cr.Status.Replsets[replset.Name].Initialized &&
-		cr.Status.Replsets[replset.Name].Status == api.AppStateReady &&
-		cr.Status.Mongos != nil &&
-		cr.Status.Mongos.Status == api.AppStateReady &&
-		replset.ClusterRole == api.ClusterRoleShardSvr &&
-		len(mongosPods) > 0 && cr.Spec.Sharding.Mongos.Size > 0 {
-
-		mongosSession, err := r.mongosClientWithRole(ctx, cr, api.RoleClusterAdmin)
-		if err != nil {
-			return api.AppStateError, nil, errors.Wrap(err, "failed to get mongos connection")
-		}
+		replset.ClusterRole == api.ClusterRoleShardSvr {
+
+		rsStatus := cr.Status.Replsets[replset.Name]
+
+		if len(mongosPods) > 0 &&
+			rsStatus.Initialized &&
+			rsStatus.Status == api.AppStateReady &&
+			cr.Status.Mongos != nil &&
+			cr.Status.Mongos.Status == api.AppStateReady {
 
-		defer func() {
-			err := mongosSession.Disconnect(ctx)
+			mongosSession, err := r.mongosClientWithRole(ctx, cr, api.RoleClusterAdmin)
 			if err != nil {
-				log.Error(err, "failed to close mongos connection")
+				return api.AppStateError, nil, errors.Wrap(err, "failed to get mongos connection")
 			}
-		}()
 
-		err = mongosSession.SetDefaultRWConcern(ctx, mongo.DefaultReadConcern, mongo.DefaultWriteConcern)
-		// SetDefaultRWConcern introduced in MongoDB 4.4
-		if err != nil && !strings.Contains(err.Error(), "CommandNotFound") {
-			return api.AppStateError, nil, errors.Wrap(err, "set default RW concern")
-		}
+			defer func() {
+				err := mongosSession.Disconnect(ctx)
+				if err != nil {
+					log.Error(err, "failed to close mongos connection")
+				}
+			}()
 
-		rsName := replset.Name
-		name, err := replset.CustomReplsetName()
-		if err == nil {
-			rsName = name
-		}
+			err = mongosSession.SetDefaultRWConcern(ctx, mongo.DefaultReadConcern, mongo.DefaultWriteConcern)
+			// SetDefaultRWConcern introduced in MongoDB 4.4
+			if err != nil && !strings.Contains(err.Error(), "CommandNotFound") {
+				return api.AppStateError, nil, errors.Wrap(err, "set default RW concern")
+			}
 
-		in, err := inShard(ctx, mongosSession, rsName)
-		if err != nil {
-			return api.AppStateError, nil, errors.Wrap(err, "get shard")
-		}
+			rsName := replset.Name
+			name, err := replset.CustomReplsetName()
+			if err == nil {
+				rsName = name
+			}
 
-		if !in {
-			log.Info("adding rs to shard", "rs", rsName)
-			err := r.handleRsAddToShard(ctx, cr, replset, pods.Items[0], mongosPods[0])
+			in, err := inShard(ctx, mongosSession, rsName)
 			if err != nil {
-				return api.AppStateError, nil, errors.Wrap(err, "add shard")
+				return api.AppStateError, nil, errors.Wrap(err, "get shard")
 			}
 
-			log.Info("added to shard", "rs", rsName)
-		}
+			if !in {
+				log.Info("adding rs to shard", "rs", rsName)
+				err := r.handleRsAddToShard(ctx, cr, replset, pods.Items[0], mongosPods[0])
+				if err != nil {
+					return api.AppStateError, nil, errors.Wrap(err, "add shard")
+				}
 
-		rs := cr.Status.Replsets[replset.Name]
-		t := true
-		rs.AddedAsShard = &t
-		cr.Status.Replsets[replset.Name] = rs
+				log.Info("added to shard", "rs", rsName)
+			}
 
+			rsStatus.AddedAsShard = ptr.To(true)
+			cr.Status.Replsets[replset.Name] = rsStatus
+		} else {
+			return api.AppStateInit, nil, nil
+		}
 	}
 
 	if replset.Arbiter.Enabled && !cr.Spec.Sharding.Enabled {