Tuesday morning notes as Nats prepare to face White Sox

Some Tuesday morning odds and ends to whet your appetite before the Nationals open their three-game interleague series against the White Sox in Chicago (to which I am currently en route)...

* The Nationals are catching a break this week when it comes to the White Sox's rotation ... sort of.

The good news: They're missing both Chris Sale (9-2, 2.54 ERA) and Jose Quintana (5-6, 2.58). The bad news (potentially): They're getting James Shields making his Chicago debut.

Shields, who was acquired from the Padres over the weekend, will be taking the mound at U.S. Cellular Field on Wednesday night, and certainly the veteran right-hander will be motivated after the way things ended in San Diego. The 34-year-old right-hander was just 2-7 with a 4.28 ERA in 11 starts, not an ideal stat line for a guy less than a year-and-a-half into a four-year, $75 million contract.

Shields was a far more effective pitcher during his two seasons in Kansas City (27-17, 3.18 ERA in 68 starts from 2013-14) and he'll now hope to recapture what he had back in the AL Central again. Whether he's able to do that, and whether any of that will be a factor Wednesday night against the Nationals, remains to be seen.

The pitching probables for the entire series: Joe Ross vs. Mat Latos tonight, Max Scherzer vs. Shields on Wednesday, Gio Gonzalez vs. Carlos Rodon on Thursday.

* Ryan Zimmerman returns to the Nationals lineup tonight, and perhaps not a moment too soon for a club that just has not been able to find a consistent offensive rhythm this season.

Zimmerman, who spent the weekend on the paternity leave list after his wife, Heather, gave birth to the couple's second daughter, was swinging a hot bat before leaving the club. Over his last 10 games, he's hitting .333 with three homers and a 1.008 OPS, perhaps the long-awaited sign that he's ready to go on his annual summer tear through the rest of the league.

The Nationals sure hope that's the case. As they also hope is the case for Anthony Rendon (1.045 OPS over his last 17 games). And as they probably hope is the case for Bryce Harper on the heels of his three-hit game Sunday in Cincinnati.

The Nationals desperately need to start getting consistent offense from anybody other than Daniel Murphy and Wilson Ramos. Here's a crazy fact: Murphy (.384) and Ramos (.350) currently own the two highest batting averages among all National Leaguers with at least 170 plate appearances. And nobody else is even close, with Ryan Braun next on the list at .337.

But here's the problem: They don't have another hitter on that list until Rendon, who with his .259 average checks into 54th place. They also have the guy who currently sits 90th out of 90 NL hitters (Danny Espinosa, at .196) and the guy who is 84th (Jayson Werth, at .220). Throw in Ben Revere (batting .167 with a .222 on-base percentage in 117 plate appearances) and the Nats lineup is awfully imbalanced right now.

* Speaking of imbalanced, what's going on with Felipe Rivero? As a rookie last year, the reliever was lights-out against both left-handed (.198 average, .486 OPS) and right-handed (.200, .600) batters. This year? He's been brilliant against righties (.121, .436) but ghastly against lefties (.324, .909).

It all culminated Sunday afternoon, when Rivero walked Joey Votto on four pitches and then served up a three-run homer to Jay Bruce a few minutes later, turning a comfortable 10-5 lead into a nailbiter that nearly was blown by Jonathan Papelbon in the ninth.

Rivero's stuff is too good for this to keep up, but his struggles do underscore how fortunate the Nationals are right now to have three lefties in their bullpen, with Oliver Perez and Sammy Solis joining Rivero.

Perez is holding lefties to a .107 batting average and .362 OPS, while Solis is holding them to a .150 average and .440 OPS. That could allow manager Dusty Baker to lay off Rivero a bit, at least late in tight games with left-handed batters due up, for a while until Rivero can right himself.

But this also may help explain why the Nationals are trying to delay the activation of Matt Belisle off the disabled list as long as possible. They can't really afford to option Solis back to Triple-A Syracuse right now.