Red Sox right fielder Mookie Betts’ OPS is down more than 100 points from last season, but by one measure he is the best defensive outfielder in baseball.



Betts leads all outfielders in 3-, 4- and 5-star catches combined, according to Statcast. When I informed him of this he acted surprised, saying he had only one 5-star catch this season. (Yes, some players are aware of the Statcast measures, and I’ll get to how they work in a moment). Betts then noted that he likes to play shallow, reasoning, “If you hit it over my head, it’s got to go over the wall unless it’s hit 100 mph.”



It’s true: according to Statcast, Betts plays the second-shallowest right field in the majors, behind the Reds’ Scott Schebler (minimum 5,000 pitches; the measure includes only road games in an attempt to mitigate park effects).



Betts said that former Red Sox teammate Shane Victorino originally told him to play shallow, advising that he position himself 10 feet or more in front of where the opposing right fielder played. Red Sox first base coach Ruben Amaro Jr., who positions the team’s outfielders, often signals for Betts to move back, particularly with two outs. Regardless, Amaro said that he loves Betts’ desire to play shallow, loves that he is confident and fearless enough to position himself that way.



Now, about those Statcast ratings: catch probability is defined as the likelihood of a catch based on opportunity time (starting when the ball is released by the pitcher) and distance needed (the shortest distance an outfielder needs to make a catch). A 5-star catch carries a 0 to 25 percent chance probability, a 4-star is 26 to 50 percent, a 3-star is 51 to 75 percent.



Catches, at least according to the system, can be deceiving. When I saw the diving, full-extension grab by the Blue Jays’ Kevin Pillar on Monday night against Boston, I figured it was a 5-star catch for sure—one of the best catches I’ve ever seen. But according to Statcast, it merited only four stars.



In any case, Betts also is faring well in other defensive measures. He is the major-league leader with 27 defensive runs saved, and the top-rated right fielder according to Fangraphs.



Thinner bullpen = stronger bullpen?



The Marlins built a deep, talented bullpen as a way to protect their questionable starting rotation. Turns out that their efforts actually had a negative effect on veteran Brad Ziegler. Only after they traded relievers David Phelps and AJ Ramos in late July did Ziegler find his groove.



Ziegler, 37, returned from a 31-game absence (right back strain) on July 29, then replaced the departed Ramos as the Marlins’ closer. Since then he has been brilliant, converting all nine save opportunities and pitching 12 scoreless innings.



“We had the right idea with the uber-strong bullpen,” said Michael Hill, the Marlins’ president of baseball operations. “I just think a veteran like Ziegler needed his routine.”



Manager Don Mattingly agreed, saying it’s “easier” to manage Ziegler as a closer. Before going on the DL in late June, Ziegler had a 6.52 ERA and .848 opponents’ OPS in 29 innings in various roles.



“He’s older,” Mattingly said. “I was using him in a role to get us out of an inning, get a groundball, sometimes in the sixth, sometimes in the seventh. [In his current role as closer] he knows when he’s going to pitch, knows when to get up and down.



“If you get him up and down, it will bother him more. You try not to do it to anybody, but especially him. You get him up and down, the next day he might not be available.”



“Uber-strong bullpens,” as Hill calls them, are not going out of style anytime soon. The Marlins’ experience, though, demonstrated that they occasionally can be difficult to manage. Mattingly had almost too many arms to sort through, and the trades gave him a clearer path to the ninth, with Kyle Barraclough frequently setting up Ziegler.



“You’re exactly right,” Hill said. “The whole premise was to try to make it as deep as possible. But when you have multiple guys who are accustomed to being back-end guys, it’s an adjustment to tell them they’re going to be out there in the sixth inning when it’s probably an hour earlier or three innings earlier than they’re used to being in a game.”



Mets’ Rosario learning quickly



The Mets love that 21-year-old rookie shortstop Amed Rosario is a sponge. The day after every game, hitting coach Kevin Long shows Rosario video of his previous night’s at-bats, and they review how he handled the strike zone.



Long said he also included former major-league pitcher and ESPN analyst Rick Sutcliffe in a recent conversation with Rosario to drive home a point about plate discipline. The discussion began with Long talking about an at-bat in which the Yankees’ Sonny Gray struck out Rosario on three straight sliders.



“When you get a guy to swing at a slider down and away,” Long asked Sutcliffe, “what would you do?”



“Throw it again,” Sutcliffe responded.



“What would you then do on 0-2?” Long asked.



“Throw it a little more down, a little more away,” Sutcliffe replied.



For Rosario, Long said, it was a lesson...