diff --git a/changelog/@unreleased/pr-1883.v2.yml b/changelog/@unreleased/pr-1883.v2.yml
new file mode 100644
index 000000000..300cec30b
--- /dev/null
+++ b/changelog/@unreleased/pr-1883.v2.yml
@@ -0,0 +1,5 @@
+type: fix
+fix:
+  description: Re-add null check for exclude rule
+  links:
+  - https://github.com/palantir/gradle-baseline/pull/1883
diff --git a/gradle-baseline-java/src/main/groovy/com/palantir/baseline/plugins/BaselineExactDependencies.java b/gradle-baseline-java/src/main/groovy/com/palantir/baseline/plugins/BaselineExactDependencies.java
index 2aa1cb10a..fd8eab1c2 100644
--- a/gradle-baseline-java/src/main/groovy/com/palantir/baseline/plugins/BaselineExactDependencies.java
+++ b/gradle-baseline-java/src/main/groovy/com/palantir/baseline/plugins/BaselineExactDependencies.java
@@ -18,6 +18,7 @@
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableMap.Builder;
 import com.google.common.collect.ImmutableSet;
 import com.palantir.baseline.tasks.CheckImplicitDependenciesParentTask;
 import com.palantir.baseline.tasks.CheckImplicitDependenciesTask;
@@ -231,10 +232,15 @@ private static String getCompileConfigurationName(SourceSet sourceSet) {
     }
 
     private static Map<String, String> excludeRuleAsMap(ExcludeRule rule) {
-        return ImmutableMap.<String, String>builder()
-                .put("group", rule.getGroup())
-                .put("module", rule.getModule())
-                .build();
+        // Both 'ExcludeRule#getGroup' and 'ExcludeRule#getModule' can return null.
+        Builder<String, String> excludeRule = ImmutableMap.builder();
+        if (rule.getGroup() != null) {
+            excludeRule.put("group", rule.getGroup());
+        }
+        if (rule.getModule() != null) {
+            excludeRule.put("module", rule.getModule());
+        }
+        return excludeRule.build();
     }
 
     /** Given a {@code com/palantir/product/Foo.class} file, what other classes does it import/reference. */