5 more intriguing Red Sox projections

Baseball projection systems aren't a toy, but they also aren't gospel or a guarantee that certain things will happen for sure. They're a helpful guess, albeit a sophisticated one, at what could go on with a team or a player or the league as a whole. This mostly means that projections tend to need a little more explanation than whatever stat line they spit out, and that's our goal here today: we'll look at five Red Sox projections from Baseball Prospectus' PECOTA system that stood out, whether that was for good or bad reasons.

If you're feeling deja vu, yes, we already hit on five Red Sox PECOTA projections that intrigued us, and introduced them the same way. The difference now is that PECOTA's percentile forecasts are out, giving us a whole different level to analyze.

In short, your standard projection is a weighted mean -- it's the average of a range of projections, from best-case to worst-case, which attempts to give you the most-likely outcome. There is plenty to learn from what PECOTA believes the best- and worst-case scenarios are for a player, though, so that's what we'll delve into this time.

Mookie Betts' greatest would be incredible

PECOTA was a big fan of Mookie Betts, even for his standard projection, which put him at .284/.360/.422 with a .291 True Average (TAv, Baseball Prospectus' version of wOBA, except on a batting average scale where .260 is always average thanks to math). It's not surprising, then, that his best-case 90th percentile forecast sees him as a star who would easily win the AL Rookie of the Year award if he were only eligible. He's projected for a .325/.407/.485 line and .329 TAv, and over 700 plate appearances would be worth roughly seven wins -- and that's without PECOTA thinking he's more than an average defensive outfielder.

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It's an unlikely 2015 outcome for Betts, sure, but it's still heartening to see that even his 10th percentile -- or worst-case -- forecast has him hitting .236/.306/.350, which is below-average but well above replacement level. If the worst Betts is expected to do is struggle at 22 the same way Xander Bogaerts did last summer, that's not bad at all, especially when you consider it's in the range of least-likely outcomes.

Xander Bogaerts' breakout is still in the cards

Speaking of Bogaerts, PECOTA's standard projection for him was good, but not glowing, thanks to his uninspiring rookie campaign. At the 20th and 10th percentile levels, the projection system sees Bogaerts basically repeating his disappointing 2014, and that itself is a positive. What brightens things up that much more, though, is seeing PECOTA project a four-win season with a .288/.355/.451 line at the 90th percentile level. If Bogaerts hits that at short, he's not quite a star, but he's one of the better players at the position in the league even with his sub-par defense. If his glove improves a bit and his bat doesn't quite make it to those levels, he can be worth about the same.

The most significant part of this projection is that PECOTA hasn't given up on Bogaerts just because he had a season-long bump in the road. He's still young, and he still has a whole lot of success behind him that could still translate to the majors.

David Ortiz is an ageless mystery

PECOTA doesn't know what to do with Big Papi anymore. At this point, the system is comping him to late-career Hank Aaron, who was still a tremendous player, and Manny Ramirez at the same age, who was a joke with 17 plate appearances, none of them good. Those are his first and second most comparable players in history. And yet, as his percentile forecasts suggest, PECOTA doesn't seem to believe its own comparables: Ortiz's worst-case projection has him hitting .242/.328/.435, which would be at least average at DH.

PECOTA also doesn't see a huge risk of injury, with the 39-year-old's minimum plate appearance forecast coming in at 547, almost enough to unlock the full financial potential of his 2016 club option. As much as we all love Ortiz -- and we do -- this all screams that PECOTA just doesn't know how to handle Ortiz anymore, more so than that he's an ageless superhero. Then again, PECOTA also projected him to finally produce a sub-replacement level line when he's 46 years old in 2022, so maybe its just preparing us for a whole lot more Ortiz than he's under contract for.

On the best-case side, PECOTA thinks Ortiz has another five-win season at the plate in him. That would undoubtedly be one of the top performances in the history of 39-year-old's in baseball history, so we'll see, but Ortiz has made a habit of making it onto those kinds of lists of late.

Rusney Castillo is probably going to be good

Rusney Castillo's mid-range projection was for .279/.345/.441, which would be tremendous from the rookie outfielder. His high-end projection has him as a star, seven-win player, though, while his bottom-end is bad, but not out of the game bad. His 10th percentile forecast suggests he could have a replacement level season at the plate but still create value with his defense, which would be a tough use of his age-27 season and cause worry going forward, but remember, it's also only as likely an outcome as Castillo being the next Carlos Gomez.

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His 20th percentile forecast would result in an average player over the course of a full season, so chances are good that Castillo will be, well, good. Whether he actually plays a full season's worth of games remains to be seen, but if the ones he does participate in are useful and everyone else is playing well, who cares?

The Red Sox rotation isn't totally hopeless

Previously when looking at PECOTA's Red Sox rotation projections, we noted that the system only liked Clay Buchholz, and even that was mostly in a relative sense. A lot of the issues had to do with how Prospectus and PECOTA measure pitcher effectiveness and value, so it wasn't something to get worked up about since the Red Sox had built a staff we knew in advance would be loathed by PECOTA. What remained to be seen was whether the system thought there was any hope at all, or if all was darkness.

The worst-case scenarios are pretty awful, as you can imagine, but they are mostly offset by the best-case side of things. PECOTA has not forgotten that Buchholz has rotation-leading upside. PECOTA thinks Porcello's best-case is basically replicating his 2014, but hey, at least the system admits it's a possibility. It sees Justin Masterson returning to form, Wade Miley as an above-average innings horse, and while it doesn't project Joe Kelly to those Cy Young numbers he's promised us, it does admit there is a potential universe where he's a productive member of Red Sox society.

That's all I wanted from PECOTA, and from most people who don't think the Sox have enough pitching. Just admit that there is a chance all of these dudes could be better than you are giving them credit for. They might not be, but don't deny the possibility.