diff --git a/pipes/WDL/workflows/terra_tsv_to_table.wdl b/pipes/WDL/workflows/terra_tsv_to_table.wdl
index 1d48f46e9..fdfb4dc20 100644
--- a/pipes/WDL/workflows/terra_tsv_to_table.wdl
+++ b/pipes/WDL/workflows/terra_tsv_to_table.wdl
@@ -13,7 +13,7 @@ workflow terra_tsv_to_table {
     }
 
     input {
-        Array[File]+ tsv_files
+        Array[File?]+ tsv_files
     }
 
     call terra.check_terra_env
@@ -30,4 +30,4 @@ workflow terra_tsv_to_table {
             workspace_name   = check_terra_env.workspace_name,
             terra_project    = check_terra_env.workspace_namespace
     }
-}
\ No newline at end of file
+}