diff --git a/clients/drcachesim/common/options.cpp b/clients/drcachesim/common/options.cpp
index f5c65931ac5..bb875fcc5af 100644
--- a/clients/drcachesim/common/options.cpp
+++ b/clients/drcachesim/common/options.cpp
@@ -1,5 +1,5 @@
 /* **********************************************************
- * Copyright (c) 2015-2019 Google, Inc.  All rights reserved.
+ * Copyright (c) 2015-2020 Google, Inc.  All rights reserved.
  * **********************************************************/
 
 /*
@@ -175,7 +175,8 @@ droption_t<bool> op_coherence(
 droption_t<bool> op_use_physical(
     DROPTION_SCOPE_CLIENT, "use_physical", false, "Use physical addresses if possible",
     "If available, the default virtual addresses will be translated to physical.  "
-    "This is not possible from user mode on all platforms.");
+    "This is not possible from user mode on all platforms.  "
+    "This is not supported with -offline at this time.");
 
 droption_t<unsigned int> op_virt2phys_freq(
     DROPTION_SCOPE_CLIENT, "virt2phys_freq", 0, "Frequency of physical mapping refresh",
diff --git a/clients/drcachesim/tracer/instru_offline.cpp b/clients/drcachesim/tracer/instru_offline.cpp
index ec45c8c1285..c19088d5536 100644
--- a/clients/drcachesim/tracer/instru_offline.cpp
+++ b/clients/drcachesim/tracer/instru_offline.cpp
@@ -220,6 +220,9 @@ offline_instru_t::get_entry_size(byte *buf_ptr) const
 addr_t
 offline_instru_t::get_entry_addr(byte *buf_ptr) const
 {
+    // TODO i#4014: To support -use_physical we would need to handle a PC
+    // entry here.
+    DR_ASSERT(!type_is_instr(get_entry_type(buf_ptr)));
     offline_entry_t *entry = (offline_entry_t *)buf_ptr;
     return entry->addr.addr;
 }
diff --git a/clients/drcachesim/tracer/tracer.cpp b/clients/drcachesim/tracer/tracer.cpp
index fa049ef4afc..f77d383681b 100644
--- a/clients/drcachesim/tracer/tracer.cpp
+++ b/clients/drcachesim/tracer/tracer.cpp
@@ -1764,6 +1764,10 @@ drmemtrace_client_main(client_id_t id, int argc, const char *argv[])
         instru = new (placement) offline_instru_t(
             insert_load_buf_ptr, op_L0_filter.get_value(), &scratch_reserve_vec,
             file_ops_func.write_file, module_file, op_disable_optimizations.get_value());
+        if (op_use_physical.get_value()) {
+            /* TODO i#4014: Add support for this combination. */
+            FATAL("Usage error: -offline does not currently support -use_physical.");
+        }
     } else {
         void *placement;
         /* we use placement new for better isolation */