Friars' lineup gets new look ... and then another

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It’s not like Mike Shildt to overhaul his starting lineup. Sure, the Padres’ manager likes to tinker at the bottom. Occasionally, he’ll rearrange in the middle, based on platoons. But a full-on shakeup at the top? Those have been rare.

Except, apparently, for this week.

When Jackson Merrill returned from the injured list on Sunday, Shildt had a surprise in store, moving Merrill up and Luis Arraez down. Three days later, another surprise: Arraez was suddenly in the top spot, with Manny Machado up to No. 2 and Fernando Tatis Jr. down at four.

“When you have good players, it creates a lot of options,” Shildt said. “Those first four guys are somewhat interchangeable. Just trying to find the right mix.”

Shildt noted that the midway point of the season -- which comes Friday -- felt like the right time to experiment with the lineup. There’s no telling which version he’ll use moving forward. As he noted, there aren’t any wrong answers with that quartet. But there are certainly pros and cons to each lineup.

Let’s break them down:

The original
1. Tatis, RF
2. Arraez, 1B
3. Machado, 3B
4. Merrill, CF

The Padres used this lineup from the start -- at least when they’ve had that group healthy. But it’s worth remembering that this alignment came as a surprise on Opening Day, after Arraez batted in the leadoff spot nearly all of last season (and Spring Training).

Clearly, there’s plenty to like about Tatis in the top spot. He wreaks havoc on the bases, and he’s the franchise leader in leadoff home runs. You don’t want to give him pitches to hit. But you also don’t want to put him on base.

There’s even more to like about Tatis in the leadoff spot with Arraez behind him. It creates holes in the infield for Arraez to exploit. And with Arraez’s contact-oriented approach, Tatis’ baserunning gets highlighted even further.

The rest is self-explanatory. Machado has thrived his entire Padres tenure hitting at No. 3. Merrill, meanwhile, is more a slugging threat and less an on-base threat. (You know, the kind of guy you might want hitting cleanup.)

For nearly three months, the Padres were fine with this alignment. Until Sunday …

Flipping the lefties
1. Tatis, RF
2. Merrill, CF
3. Machado, 3B
4. Arraez, 1B

“Wherever he puts me,” Merrill said, “I’ll hit.”

The difference being, over the course of a season, Merrill gets more chances to hit if he’s batting second instead of fourth.

That’s the simple explanation behind this alignment. With due respect to Arraez, the Padres’ three best hitters have been Tatis, Merrill and Machado (in no particular order). They’re the team’s three leading hitters in OPS and wRC+. Those are the three hitters you want at the plate most frequently.

Shildt, however, did not frame the change as a means to get Merrill ahead of Arraez. That’s presumably because he doesn’t want the decision viewed as a slight on Arraez. But there’s another justification for Arraez in the cleanup spot.

Over the course of his managerial career, Shildt has preferred contact hitters in the middle of the order, where they’re likelier to bat with runners on base. It frees up holes, and it allows the Padres to get creative on the bases. Arraez, of course, might be the best contact hitter in the sport.

“Luis is a presence wherever you put him,” Shildt said. “He just is a quality at-bat, clearly -- a three-time batting champion. But he also knows how to drive in runs. It just frees up the top for Jackson and Tati to go ball out, and [you] have Luis sitting there to be able to use his magic wand.”

Makes sense, right? Until…

A wholesale shakeup
1. Arraez, 1B
2. Machado, 3B
3. Merrill, CF
4. Tatis, RF

Just like that, on Wednesday, Arraez was back in the leadoff spot -- and he knocked in the only run in the Padres’ 1-0 victory over the Nationals.

“Same job,” Arraez said. “I don’t need to change anything. … When I talked with Mike, I said, ‘Hey, if you need me leadoff, second, ninth, I just need the opportunity to go out there and play.’”

There’s logic to Arraez at the top, even if he’s not the same threat as Machado/Tatis/Merrill. His .366 career on-base percentage is higher than any of that group -- and isn’t that what you’re looking for in the top spot in the lineup?

Plus, hitting your lefties first and third rather than second and fourth has a major benefit. The biggest weakness with the Padres’ lineup construction was its obvious left-right lanes.

The 5-7 spots have been occupied by Gavin Sheets (lefty), Xander Bogaerts (righty) and Jake Cronenworth (lefty). There’s a downside to batting Arraez or Merrill fourth and stacking three lefties in a four-batter span. If you’re an opposing team, you use your top lefty relievers for that lane, and you use your top righties for the rest.

Theoretically, the Padres will get favorable matchups more often with this lineup construction. It comes at the cost of Tatis, one of their most dynamic offensive weapons, dropping to fourth. But there are worse problems to have than batting a perennial 40-homer threat in the cleanup spot.