diff --git a/var/spack/repos/builtin/packages/opencv/package.py b/var/spack/repos/builtin/packages/opencv/package.py
index adddbc1857..41766da0de 100644
--- a/var/spack/repos/builtin/packages/opencv/package.py
+++ b/var/spack/repos/builtin/packages/opencv/package.py
@@ -68,7 +68,7 @@ class Opencv(CMakePackage):
     variant('java', default=False,
             description='Activates support for Java')
     variant('openmp', default=False, description='Activates support for OpenMP threads')
-    variant('core', default=False, description='Include opencv_core module into the OpenCV build')
+    variant('core', default=True, description='Include opencv_core module into the OpenCV build')
     variant('highgui', default=False, description='Include opencv_highgui module into the OpenCV build')
     variant('imgproc', default=False, description='Include opencv_imgproc module into the OpenCV build')
     variant('jpeg', default=False, description='Include JPEG support')
@@ -90,6 +90,7 @@ class Opencv(CMakePackage):
     depends_on('qt', when='+qt')
     depends_on('java', when='+java')
     depends_on('py-numpy', when='+python', type=('build', 'run'))
+    depends_on('protobuf@3.1.0', when='@3.3.0:')
 
     extends('python', when='+python')