diff --git a/src/libraries/System.IO.Compression/src/System.IO.Compression.csproj b/src/libraries/System.IO.Compression/src/System.IO.Compression.csproj
index df5985bcfdd8bb..e2a7adee12f579 100644
--- a/src/libraries/System.IO.Compression/src/System.IO.Compression.csproj
+++ b/src/libraries/System.IO.Compression/src/System.IO.Compression.csproj
@@ -15,7 +15,6 @@
     <Compile Include="$(SharedOpenSourcePath)System\IO\Compression\ZipVersion.cs" />
     <Compile Include="System\IO\Compression\DeflateManaged\BlockType.cs" />
     <Compile Include="System\IO\Compression\DeflateManaged\DeflateManagedStream.cs" />
-    <Compile Include="System\IO\Compression\DeflateManaged\FileFormats.cs" />
     <Compile Include="System\IO\Compression\DeflateManaged\HuffmanTree.cs" />
     <Compile Include="System\IO\Compression\DeflateManaged\InflaterManaged.cs" />
     <Compile Include="System\IO\Compression\DeflateManaged\InflaterState.cs" />
diff --git a/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/DeflateManagedStream.cs b/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/DeflateManagedStream.cs
index a58477161f35f1..2d398529674191 100644
--- a/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/DeflateManagedStream.cs
+++ b/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/DeflateManagedStream.cs
@@ -31,7 +31,7 @@ internal DeflateManagedStream(Stream stream, ZipArchiveEntry.CompressionMethodVa
 
             Debug.Assert(method == ZipArchiveEntry.CompressionMethodValues.Deflate64);
 
-            _inflater = new InflaterManaged(null, method == ZipArchiveEntry.CompressionMethodValues.Deflate64 ? true : false, uncompressedSize);
+            _inflater = new InflaterManaged(method == ZipArchiveEntry.CompressionMethodValues.Deflate64, uncompressedSize);
 
             _stream = stream;
             _buffer = new byte[DefaultBufferSize];
diff --git a/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/FileFormats.cs b/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/FileFormats.cs
deleted file mode 100644
index ee382170a9d4a4..00000000000000
--- a/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/FileFormats.cs
+++ /dev/null
@@ -1,13 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-
-namespace System.IO.Compression
-{
-    internal interface IFileFormatReader
-    {
-        bool ReadHeader(InputBuffer input);
-        bool ReadFooter(InputBuffer input);
-        void UpdateWithBytesRead(byte[] buffer, int offset, int bytesToCopy);
-        void Validate();
-    }
-}
diff --git a/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/InflaterManaged.cs b/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/InflaterManaged.cs
index 4f1c36834a8bbf..7fe90bbc670d81 100644
--- a/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/InflaterManaged.cs
+++ b/src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateManaged/InflaterManaged.cs
@@ -48,7 +48,6 @@ internal sealed class InflaterManaged
         private HuffmanTree? _distanceTree;
 
         private InflaterState _state;
-        private readonly bool _hasFormatReader;
         private int _bfinal;
         private BlockType _blockType;
 
@@ -75,9 +74,7 @@ internal sealed class InflaterManaged
         private readonly long _uncompressedSize;
         private long _currentInflatedCount;
 
-        private readonly IFileFormatReader? _formatReader; // class to decode header and footer (e.g. gzip)
-
-        internal InflaterManaged(IFileFormatReader? reader, bool deflate64, long uncompressedSize)
+        internal InflaterManaged(bool deflate64, long uncompressedSize)
         {
             _output = new OutputWindow();
             _input = new InputBuffer();
@@ -86,19 +83,7 @@ internal InflaterManaged(IFileFormatReader? reader, bool deflate64, long uncompr
             _codeLengthTreeCodeLength = new byte[HuffmanTree.NumberOfCodeLengthTreeElements];
             _deflate64 = deflate64;
             _uncompressedSize = uncompressedSize;
-            if (reader != null)
-            {
-                _formatReader = reader;
-                _hasFormatReader = true;
-            }
-            Reset();
-        }
-
-        private void Reset()
-        {
-            _state = _hasFormatReader ?
-                InflaterState.ReadingHeader :   // start by reading Header info
-                InflaterState.ReadingBFinal;    // start by reading BFinal bit
+            _state = InflaterState.ReadingBFinal; // start by reading BFinal bit
         }
 
         public void SetInput(byte[] inputBytes, int offset, int length) =>
@@ -137,12 +122,6 @@ public int Inflate(byte[] bytes, int offset, int length)
                 }
                 if (copied > 0)
                 {
-                    if (_hasFormatReader)
-                    {
-                        Debug.Assert(_formatReader != null);
-                        _formatReader.UpdateWithBytesRead(bytes, offset, copied);
-                    }
-
                     offset += copied;
                     count += copied;
                     length -= copied;
@@ -155,17 +134,6 @@ public int Inflate(byte[] bytes, int offset, int length)
                 // Decode will return false when more input is needed
             } while (!Finished() && Decode());
 
-            if (_state == InflaterState.VerifyingFooter)
-            {  // finished reading CRC
-                // In this case finished is true and output window has all the data.
-                // But some data in output window might not be copied out.
-                if (_output.AvailableBytes == 0)
-                {
-                    Debug.Assert(_formatReader != null);
-                    _formatReader.Validate();
-                }
-            }
-
             return count;
         }
 
@@ -200,27 +168,6 @@ private bool Decode()
                 return true;
             }
 
-            if (_hasFormatReader)
-            {
-                Debug.Assert(_formatReader != null);
-                if (_state == InflaterState.ReadingHeader)
-                {
-                    if (!_formatReader.ReadHeader(_input))
-                    {
-                        return false;
-                    }
-                    _state = InflaterState.ReadingBFinal;
-                }
-                else if (_state == InflaterState.StartReadingFooter || _state == InflaterState.ReadingFooter)
-                {
-                    if (!_formatReader.ReadFooter(_input))
-                        return false;
-
-                    _state = InflaterState.VerifyingFooter;
-                    return true;
-                }
-            }
-
             if (_state == InflaterState.ReadingBFinal)
             {
                 // reading bfinal bit
@@ -293,10 +240,7 @@ private bool Decode()
             //
             if (eob && (_bfinal != 0))
             {
-                if (_hasFormatReader)
-                    _state = InflaterState.StartReadingFooter;
-                else
-                    _state = InflaterState.Done;
+                _state = InflaterState.Done;
             }
             return result;
         }