MLB Star Power Index: Bryce Harper, the clutch god; Ronald Acuna Jr., the 40-40 threat

Welcome to the MLB Star Power Index -- a weekly temperature reading that tells us which players are owning the baseball conversation right now. While one's presence on this list is often a positive, it's not necessarily a good thing. It simply means that you're capturing the baseball world's attention for one reason or another. The players listed are in no particular order. Thanks to Brad Botkin and our compadres over at CBS NBA for letting us borrow the concept. 

View Profile
Bryce Harper PHI • RF • 3

Bryce Harper -- a.k.a., Orval Powerbeard -- has had a good first season in Philadelphia while also having a somewhat disappointing first season in Philadelphia. At this writing, Harper owns an OPS+ of 120, which, again, is good. However, it's solidly below his career norms, and it's even further shy of what Philly partisans were hoping. While one can plausibly argue that those same Philly partisans are most comfortable when smothered in the loving arms of chagrin, they want more from their $330 million sum buck. 

Then came Thursday night's baseball events: 

That was doubtless one of the most memorable clouts of Harper's career to date, and it will grow more memorable should his Phillies claw their way into the postseason. It's also fully in keeping with Harper's first season in Philly. 

Yes, this scribe is here, clothed in robes of magisterial purple, to say that Harper has for a long time in 2019 been delivering in ways that may not be detected by the usual cursory appraisals. Specifically, Harper has been clutch as all heck in his first Philly season, and that was the case even before the lil' miracle you glimpsed above. 

Consider the following relevant digits that were locked in place before he dry-gulched the Cubs

  • Harper with runners on base in 2019 had a pre-Thursday slash line of .345/.439/.645.
  • With runners in scoring position this season, he batted .378/.484/.653. 
  • With runners in scoring position and two outs, he batted .410/.540/.744. 
  • In high-leverage situations (i.e., clutch situations), Harper in 2019 had a pre-Thursday OPS of 1.018. When it's medium-leverage, Harper's OPS was .836, and when it's low-leverage (i.e., unimportant) Harper had an OPS of .805. In other words, he's been at his best when the stakes are highest, and, again, that was the case before that grand slam.
  • According to the Clutch measure at FanGraphs, which evaluates the extent to which a player steps up his production in clutch spots relative to his baseline in non-clutch spots, Harper this season had been the second-clutchest hitter in all of baseball (behind only Paul Goldschmidt of the Cardinals). Suffice it to say, he's only improved his standing in that regard.

As buccaneering nerds are fond of saying, there are clutch performances but not clutch players. This is pretty much true. For instance, Harper's clutch performance has swung widely from year to year over the course of his career. This season, it's swung far and firmly in the clutch direction. That's why Harper has been a serious boon to the Phillies this season, even if his overall numbers are an ongoing source of hand-wringing in Philly and environs. 

View Profile
Aristides Aquino CIN • RF • 44

Aristides Aquino has authored such an astounding start to his MLB career that a metaphor -- as tortured as it is mixed -- is justified: he has arrived like a comet with a rear spoiler shot out of a volcano shaped like a gun with wings. There we go. You know all about the various and sundry records he's set for most home runs through a player's first 10, 11, 12 and so on games. We're here to praise his rebuilt swing, which calls to mind a rec-league softball player fresh off a second divorce. Witness: 

As the story goes, Reds assistant hitting coach Donnie Ecker persuaded Aquino to go with a more open stance this past spring. Setting up like that affords a hitter something close to a straight on view of the pitch with both eyes, at least until the load begins. That, in turn, can improve pitch recognition. What you see on the right is indeed a maximalist open stance. "Is he about to hit a pitched ball hard and also far, or is he preparing to behead a gila monster with toxic venom?" That's a question that can be reasonably asked by the uninitiated. 

Aristides has long had jaw-dropping raw power, and now a drastic swing change seems to have unlocked his game power. Yes, he's but toe-deep into his career, but already he's flashing the kinds of exit velocities that bode very well for his future. When you see someone swinging like he's glimpsed tomorrow and discovered it doesn't exist, he is to be celebrated. When such nothing-left-to-lose swing mechanics arrive in tandem with record-breaking home run outputs, he is to be doubly to trebly celebrated. 

People, summon forth each and every fatted calf for This, Our Aristides Aquino. 

View Profile
Ronald Acuna ATL • CF • 13

Ronald Acuna Jr., assume the position -- in which the position is the athletic stance necessary to properly receive Star Power Index honors. 

Acuna is of course having a season befitting his generational talent status. Thanks to his plus defense at an up-the-middle position, excellent baserunning (he leads the NL in steals and has taken the extra base an impressive 54 percent of the time), and power outputs have put him in the NL MVP discussion. Yes, Cody Bellinger of the Dodgers is the heavy favorite, but Acuna of late has been closing the gap a bit. 

Anyhow, let's level our smoky gaze at Acuna's power and speed. Right now, Acuna has tallied 35 home runs and 28 stolen bases. Given that we're in the middle of August, those tallies put him within range of a 40-40 season. You'll recall that just four players in the entire sprawl of MLB history have pulled off this feat: 


Jose Canseco, Athletics





Barry Bonds, Giants





Alex Rodriguez, Mariners





Alfonso Soriano, Nationals





Acuna is of course in his age-21 season, so he'd become the youngest 40-40 man ever. Is he likely to pull it off? Barring injury, he'll top 40 homers and likely do so with ease. His steals total will be the challenge. Acuna ran wild in July, as he tallied 12 steals in 24 games. In August, though, he has just three stolen bases. Obviously, he's capable of registering 12 steals between now and the end of the regular season, but he's going to need to come closer to that July pace than his current August pace. Another consideration is that Acuna's Braves have a fairly comfortable lead in the NL East. If they clinch before the final days of the regular season -- a likelihood -- then Acuna may see his playing time reduced and his aggressiveness on the bases reined in so as to keep him healthy for the playoffs. 

So what does the SportsLine Projection Model say? Right now, the system tabs Acuna for nine home runs and nine stolen bases over the balance of the regular season. That would leave him with 44 home runs and 37 steals -- three thefts shy of 40-40. That passes the sniff test, as Acuna probably won't get the steals he needs to join this most exclusive club. That said, it's possible, and it won't even require a minor miracle to get him there. Whether he can become the fifth ever to reach 40-40 will give is a compelling down-the-stretch subplot. 

However, this unfolds, Acuna remains squarely on track for superstardom, and that he's emerged as one of the best players in baseball at such an unripe age suggests greatness for years to come.

View Profile
Shane Greene ATL • RP • 19

Shane Greene, thy name for these purposes is "the hazards of trading for an aging reliever having a career year writ small." 

The Braves of course swung a deal for Greene leading up to the July 31 trade deadline. Since then, Greene has pitched to an 11.81 ERA with 13 hits -- including two homers -- in 5 1/3 innings on Atlanta's watch. Already, he's lost his job as Atlanta's closer. Greene, obviously, is a better pitcher than this, but he also may not have been truly as good as he was in Detroit this season before the trade. With the Tigers in 2019, Greene registered a 1.18 ERA, but lurking behind that ERA was six unearned runs in 38 innings and an FIP of 3.70. That FIP suggested that he was purty dad-gum lucky to have that 1.18 ERA. 

Also working against the notion that Greene was likely to keep it up was his pre-2019 body of work. Even after his stuff played up following a full-time switch to the bullpen, Greene didn't approach these heights. Maybe there was stuff-based cause to think he'd truly leveled up? Nah. Greene's fastball velocity this season has been down significantly from his 2017 and 2018 levels, and nothing's drastically changed with his pitch mix. 

Of course, maybe the Braves acquired him knowing he'd gotten lucky to date and fully aware that regression ranged from possible to likely. Just as the reliever's small sample size giveth, it also taketh away. That's been the case with Greene's Atlanta tenure. He'll surely fare better at some point, but with relievers you never know entirely what you're getting. 

That's not the case with wholesome and restorative pizza, which is always delicious.

CBS Sports Writer

Dayn Perry has been a baseball writer for CBS Sports since early 2012. Prior to that, he wrote for and He's the author of three books, the most recent being Reggie Jackson: The... Full Bio

Our Latest Stories