The Improbability of a Marcus Semien

The image above represents a landmark moment in the author’s own life — and perhaps the life of anyone who derives pleasure from those instances in which the previously marginalized become less marginalized — insofar, I mean, as it demonstrates how, earlier today, Marcus Semien was the most searched-for player at FanGraphs.

On the one hand, it’s not particularly surprising that Semien would be a person of some interest at the moment: he, along with assorted other pieces, was just traded to Oakland in exchange for talented right-hander Jeff Samardzija and still-alive prospect Michael Ynoa. Curious Oakland fans — and curious other sorts of fans, too — are curious about the new additions to the club.

What’s is surprising, however, is that Semien might serve as the “centerpiece” — or an approximation thereof — in a deal that sees Jeff Samardzija (even if it’s just a year of Jeff Samardzija) going the other way.

At some level, that surprise is the product of an issue discussed in some depth by Dave Cameron earlier today — namely, that public perception of trade value is unduly swayed in favor of the brand-name player, even as the clubs themselves appear content to receive a number of lower profile, but still useful, pieces in return for stars.

Of note regarding Semien, particularly in light of his pedigree, is that he’s ascended to a point where he might be considered even a useful piece — or, a “nice little second baseman” as Cameron refers to him in the post mentioned above. Objectively speaking, the probability of Semien having made it even to this point is quite low.

There are a number of ways to estimate objectively — which is to say, without any specific consideration of his tools or performance — the likely outcome of a player’s career. Among the easiest to calculate — because they rely on readily available information — are the relevant player’s draft slot (with a consideration also of signing bonus) and also his place on industry prospect lists.

So far as the former of those is concerned, one finds — with regard to Semien — one finds that he was a sixth-round pick (signed for a typical sixth-round bonus) in the 2011 draft. While, on the one hand, being selected in the sixth round is tantamount to being recognized as one of the top-200 draft-eligible amateurs in all the country (and also Canada and also Puerto Rico), it’s also a strong argument against that same sixth-rounder’s chances of ever having a major-league career. Consider: of the 150 players selected in the sixth round between 2001 and -05, just 44 (or 29%) have since made even one appearance in the major leagues. Only four of those 150 (or 3%) have recorded a 10 WAR or greater in the majors. By comparison, 117 of the 150 players* (or, 78%) selected in the first round between 2001 and -05 have graduated, at some point, to the majors. Forty (or 27%) of those graduates from the first round have produced 10-plus wins in the majors so far.

*I’ve ignored supplementary picks to make the numbers even.

Rephrased: a first-round pick from 2001 to -05 is just about as likely to have already recorded 10 wins in the majors as a sixth-round pick from that same interval is to have appeared at all in a major-league game.

Another means by which to estimate objectively the likely future value of a prospect is to consider his place on various preseason industry lists. Semien, for his part, appeared on zero of these until the 2013-14 offseason — which is to say, his third year of eligibility for such a thing. This isn’t unsurprising: a study of a recent MLB.com top-100 prospect list revealed that 59 of the players within same had been selected either in the first or supplemental round of the amateur draft. No fewer than 15 other prospects on that same list had been signed originally as international free agents, as well. In all, only about 25% of the list consisted of players selected in the second round or later of the amateur draft. If we assume that all of those remaining players were selected between rounds two and six (i.e. Semien’s round) over, say, a period of three draft years, that’s a sample of 450 or so players from which only 25 have been regarded as among the game’s most promising. When we consider that there are also players from after the sixth round, then it’s probably fair to say that a player in Semien’s position has less than a 5% chance of appearing on any given edition of Baseball America’s top-100 list or the equivalent.

Indeed, even when he did appear on a notable offseason prospect list, it was just 91st overall on Baseball America’s. Research by Scott McKinney reveals that a prospect ranked in that area on BA’s annual top-100 list has historically developed into even just an average major-league player only about 20-25% of the time. While Semien has struggled at the major-league level, Steamer projects him to produce a 105 wRC+ and 1.9 WAR in about 500 plate appearances in 2015*. Almost precisely league average, that, in just his age-24 season.

*ZiPS is even more optimistic: a 2.4 WAR in roughly 600 PAs, according to Dan Szymbuttface.

Of course, these long odds don’t apply merely to Semien. Paul Goldschmidt and Ben Zobrist and half of the Cardinals’ most recent World Series team were all selected in the sixth round or later and omitted from notable prospect lists — and all have become average, if not markedly better than average. It follows that some of these sorts of these previously unheralded players will develop into successes. The probability of any one of them doing it, however, remains quite small.