WASHINGTON -- Dusty Baker spent much of his pregame news conference explaining why Ryan Zimmerman was still his cleanup hitter instead of Daniel Murphy. Then he went out and watched Zimmerman fail to clean up (again), while Murphy continued to rake.

On Monday afternoon, a day after Bryce Harper walked six times and Zimmerman left 14 runners on base in the Washington Nationals' 13-inning loss to the Cubs, Baker was asked about the possibility of swapping the slumping Zimmerman with No. 5 hitter Murphy, who has been as hot as anyone in baseball over the first month of the season.

“I think you guys want me to switch it up, so not yet,” Baker said to members of the media prior to Monday’s series opener against the Detroit Tigers, which the Nats won 5-4, thanks to a ninth-inning, pinch-hit homer by Clint Robinson. “If it continues, I've thought about it hard and long, but a few days doesn't merit you switching it up. I mean, if he’d gotten one hit on one of those times, you'd never even ask me this today. Not yet.”

But on Monday, it continued -- big time, to borrow one of Baker’s catchphrases.

Batting cleanup behind Harper once again, Zimmerman went 0-for-4 on Monday. Four times, he failed to hit the ball out of the infield. Three times, he came up with runners on base. Two times, he batted after Harper had walked. One time, it was an intentional pass. Zero times, Zimmerman did what his job title says he’s supposed to do.

Meanwhile Murphy, went 2-for-4 with a homer and three RBIs. He’s now hitting .398 to lead the majors, and his 1.102 OPS ranks second. He also has 16 multihit games, the most in baseball. In others words, he’s really good at swinging the bat. Or he’s really hot. Or both. Regardless, if you’re Baker and you’re looking for someone to offer added lineup protection so that opposing hurlers can’t simply pitch around Harper, you could do a lot worse than Murphy.

And yes, in case you haven’t heard, Harper could use a little more protection. The first three weeks of the season, over 40 percent of the pitches that the reigning National League MVP was seeing were in the strike zone. The next two weeks, that percentage dipped into the low 30s. In the week that just ended on Sunday, only 21.4 percent of the offerings that came Harper’s way were in the strike zone. On the season, his 39 percent zone rate is the second lowest in the National League, which should come as no surprise.

What does come as a surprise is how ineffective Zimmerman has been at making opposing pitchers pay for avoiding Harper.

A career .282 hitter with a knack for driving in runs, the 31-year-old first baseman is hitting just .227 with 12 RBIs. Even more alarming, Zimmerman is hitting just .196 with men on base. But wait, it gets worse: With men on base and two outs, Zimmerman’s average drops to .136.

Meanwhile, Murphy continues to look a whole lot like the best hitter in baseball. Not to mention, in the five games Murphy has hit cleanup, Harper has only been walked twice, as opposed to the 30 times he has walked in 27 games hitting in front of Zimmerman.

So why not juggle the lineup a little? Why not flip-flop Murphy and Zimmerman? Even if it's only temporary, until Zimmerman finds his groove, which he almost certainly will, and likely sooner rather than later. Why not shuffle the deck until then?

There are plenty of reasons, many of which Baker has already enumerated during any of the multiple sessions in which he has been grilled on the subject.

For starters, putting lefties Harper and Murphy back-to-back makes it easier for opposing managers to match up with their bullpen late in games, even if both hitters tend to fare relatively well against southpaws. Catcher Wilson Ramos, who has been hot too and could be a righty cleanup option, is prone to hitting into double plays. Then there’s the mental collateral damage.

“I’ve been where Zim has been before,” said Baker, who as a young big leaguer was charged with the unenviable task of hitting behind Hank Aaron. “And unless you've been in Zim's shoes, then you don't really know what it's like psychologically to feel that somebody still has faith in you versus a fair-weather manager or fair-weather fan. I'm not a fair-weather type of guy. I'm not a forever guy, either. But a couple days is not near as long as forever.”

Maybe not. But a couple of more days like Sunday and Monday and it might start to feel like forever.