diff --git a/netty/src/main/java/io/grpc/netty/NettyServerHandler.java b/netty/src/main/java/io/grpc/netty/NettyServerHandler.java
index 79b10236227..17ec63c4c47 100644
--- a/netty/src/main/java/io/grpc/netty/NettyServerHandler.java
+++ b/netty/src/main/java/io/grpc/netty/NettyServerHandler.java
@@ -761,7 +761,8 @@ private final class KeepAlivePinger implements KeepAliveManager.KeepAlivePinger
     @Override
     public void ping() {
       ChannelFuture pingFuture = encoder().writePing(
-          ctx, false /* isAck */, KEEPALIVE_PING_BUF, ctx.newPromise());
+          // slice KEEPALIVE_PING_BUF because tls handler may modify the reader index
+          ctx, false /* isAck */, KEEPALIVE_PING_BUF.slice(), ctx.newPromise());
       ctx.flush();
       if (transportTracer != null) {
         pingFuture.addListener(new ChannelFutureListener() {