McLouth (shoulder) has been slow to recover from treatment and underwent an enhanced MRI on Monday, Mark Zuckerman of CSNWashington.com reports. The Nationals hope Monday's examination will reveal a clearer timetable for McLouth's recovery, but expectations of a forthcoming return should probably be tempered at this point. The Nationals signed Nate Schierholtz to a minor league contract earlier in the day Monday, making him something of an insurance option for McLouth, given his standing as a left-handed hitting reserve outfielder.