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DJ Peterson & the Wisdom of First Round First Basemen

In June the Seattle Mariners took the University of New Mexico’s D.J. Peterson with the twelth overall pick in the Rule 4 Amateur Draft. Peterson represented one of the safest, most easily projectable bats in the draft class. He had mashed the ball all Spring for the Lobos and led the team to a Super Regional berth. His 18 home runs were good for third most in Division 1 – although he did play his home games in a very homer-friendly park. His short, explosive swing and quick hands excited scouts and appealed to scouting directors looking for a bat that could help relatively quickly. With a strong pro debut Peterson finished 2013 looking like a player every team would be glad to have in their farm system. There remains some questions as to whether Peterson can stay at third base in the long term though, and where he plays could swing his value pretty drastically.

As someone who covers amateurs and the draft fairly extensively I often see fans that prefer their team avoid a player like Peterson if there is some question of him moving to first base. After all, the defensive spectrum and conventional baseball wisdom tells us that good teams are built up the middle, with players on the right side of the defensive spectrum. Talking to amateur scouts I encounter a different attitude. They find it more than difficult enough to “hit” on a player and are quite often happy to find a safer choice like Peterson than they can project as a major league bat. After all, the general success rate of any first rounder making the majors isn’t great, so for many it’s very enticing to find a player you’re reasonably confident will hit in the big leagues. Both viewpoints have merit, of course. Personally, I have to be really convinced a player has a special bat for me to endorse him as a top of the first round pick. The offensive threshold expected at first base is just so lofty that it troubles me some to spend early picks on players with uncertain profiles. A prospect can develop into an above average major league hitter and still be only the 16th best first baseman in the majors (as in the case of  Nick Swisher this season with a .336 wOBA). When calculating WAR the positional adjustment for third base is +2.5, which is the same as that for second base and center field. The adjustment for first base is -12.5. Given the broad range of available quality hitters in free agency at first base and the extreme developmental demands on a first base prospect’s bat the question that then comes to mind is whether it makes sense for teams to draft a first baseman in the 1st round.

History of 1st rd First Base Picks

To investigate this I looked at the first basemen drafted in the 1st round and 1st supplemental round over the last twenty years. Why twenty years? Teams are clearly approaching the draft differently in recent years so I didn’t want to go too far back. Why first round? Why not second and third also or early rounds? First round picks have premium money commitments and a stigma attached to them. Yes, this is somewhat arbitrary, but I wanted to see what I could find out by asking the question anyway. Here are the First Basemen drafted in the 1st and 1st Supplemental Rounds since 1993:


How we define a first base draft pick is obviously an issue. While there are many clearly first base only players, a good amount of players end up at first after not being able to handle another position – much as we fear in the case of Peterson. On this spreadsheet I have generally sifted the players into two groups – Type A and Type B. Type A players were draftees who were expected all along to play first base or designated hitter only. Type B players were drafted at or given a chance to play another position but couldn’t cut it. Sometimes it was a lack of skills or stunted development. Other times their bodies developed unexpectedly in a way that pushed them towards first base.

It’s also worth noting that Type Bs generally seem to come in a few recognizable flavors. A common archetype is slow, unathletic plodders who are given a chance to fit in an outfield corner (typically left field) but who remain firmly entrenched at the bottom of the defensive spectrum because of their athleticism or body type. Then there are fringy defensive catchers who have some modicum of ability behind the plate, but who will only fit at first base if they have to move off of catcher. Peterson is in the third base/first base/corners mold. This group is full of shaky defenders at the hot corner who lack the first step, footwork, range, actions or arm to stick at third base. When we sort the draftees into Types A and B we see a little better the type of players Peterson resembles. He’s not all that similar to a Prince Fielder, who we knew would be a first baseman or designated hitter by the age of 12 or so!

I do have a couple other concerns here. First off, I worry that looking at just first rounders ignores the former economic realities of the draft. In fact, I’m quite sure this is the case, but the bottom line is that I have far less concern with a team giving a big first base bat first round money in the fourth or seventh round under the old rules than I do with the opportunity loss incurred taking a similar player tenth overall. Second, I worry that perhaps we’re just seeing how good teams are (or were) at evaluating bat-first amateurs rather than measuring the general wisdom of taking a first base prospect in the first round.  So to look a little closer, let’s parse by players taken in the top 15, too. Generally players taken in the first half of the first round would be more consensus first round types under any set of rules. Hopefully that will eliminate some of the noise of signability guys, etc… that we find in the supplemental round.

So how successful are teams at taking 1B only or probably 1B types in the first round?

Out of 54 total players identified:

Among Type A’s (Always 1B only prospects)

Among Type B’s (Played other positions but ended up at 1B)

Among College Draftees

Among High School Draftees

Among Top 15 Overall Draftees

So much depends on how we define “success.” A few years back Jeff Zimmerman placed the league average wOBA for a first baseman at .350 and replacement level for a first baseman at .313. That seems as good a measure as any other, and using it we find 13 out of 54 players have reached the majors and posted a career wOBA greater than or equal to .350. That’s a little more than 24% of the time. Again, I’m not drawing conclusions here… just observing and asking questions. As this series continues we’ll have a better scale for comparison.

Where Peterson fits

I haven’t gotten an extended look at Peterson in person, but from what I saw on the Cape, the broadcasts I’ve watched and the reports I get I really question whether Peterson has the actions or range to stick at third base in the long term. You can probably play him there and he can be a solidly below average defender that won’t embarrass himself… but it’s not going to be a great fit. Compounding the problem is how fast Peterson may advance through the minors. His bat may move quickly enough the M’s decide they don’t want to wait for him to try and improve at third base. At first base this is still a quality bat and a solid regular. I don’t see a special bat though, and that really limits how excited I can get about this prospect. In the context of the Mariners needing offense (and hopefully quickly) I do think this pick looks somewhat better. While I do think Peterson will be a solid major league hitter this just isn’t how I would prefer to use a top 15 pick in most years.