McLouth has suffered a number of setbacks during his rehab process and opted to get a second opinion because the shoulder wasn't healing properly. He was scheduled to undergo an arthrogram MRI -- effectively a joint X-ray -- on Monday to help determine the full extent of the injury and how much time it will force him to miss.
"It was by design that we went after [Schierholtz]," general manager Mike Rizzo said. "He's had great success as a pinch-hitter. He can play all three outfield positions above average. He throws well. He still runs well. He's got some pop from the left side of the plate. And as you see by our bench, we're a little short on left-handed power bats."
Manager Matt Williams also admitted that his bench is "right-handed heavy" in McLouth's absence despite having two switch-hitters in infielders Danny Espinosa and Asdrubal Cabrera. Schierholtz, who hit .192 in 99 games for Chicago this season, could help to even that discrepancy while also providing a proven and experienced bat.
Schierholtz had his best season in 2013, with the Cubs, batting .251 with a career-best 21 homers, 32 doubles, 56 extra-base hits and 56 runs.
"You have to have options. So what we don't have right now is that quote-unquote lefty off the bench," Williams said. "[Schierholtz] was out there and available, and given his history and the way he's played, it was the logical thing to do. … You have to make sure that you're covered and you have options. And he's a good player. He had a great season last year, and he's got experience doing what he may potentially be asked to do here."
Rizzo said the Nationals attempted to acquire Schierhotlz via trade on a number of occasions during past seasons, but the deals never worked out.
The left-handed slugger is expected to arrive at Triple-A Syracuse on Tuesday, and Rizzo said Schierholtz would remain there as long as necessary to regain his form. The outfielder hasn't seen action since Aug. 5.
"We know when the last time he's played, so we're going to gauge how he feels," Rizzo said. "We'll get him as many at-bats as needs down there until we bring him up."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. Daniel Popper is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.