Let’s Take a Quick Look at Team Depth
This is going to have a lot of caveats, so I should try to sell you on it first. Team depth — is it important? The correct answer is, “sometimes, yeah, although not all the times.” See, depth is no one’s primary weapon. A team comes first with its stars, with its everyday regulars. But depth is one of those things that commonly becomes important, because bad things happen, and they happen indiscriminately. Depth is basically like health insurance, and while a team can have a successful season without very much of it, the odds are eventually it’s going to come into play. Which is why some teams talk openly about trying to accumulate it.
A few front offices this past winter talked about how the average team needs way more than five starting pitchers. I think by now we all have a good understanding of that. Then sometimes you also get teams like the 2015 Mets, who wound up in need of position-player depth. Ideally a team will begin a season with plenty of in-house support, and below, I’ve made an attempt to quantify what teams currently have. It’s not a perfect, inarguable attempt. It’s just the attempt you’re reading right now.
There’s just not a wonderful way to do this. You can eyeball it, but then you can’t do league-wide comparisons. Depth in some sense is a feel thing, but I wanted to try to stay as objective as possible, because I don’t want to interject my own opinion. If you have your own ideas, please feel free to chime in, but there’s nothing for me to do now but proceed.
Here’s how I decided to go about this: I pulled every team’s projected position players and projected starting pitchers from our team depth charts. I left out relievers, because relievers are tricky, and depth relievers are relatively unimportant, and it gets weird when you try to blend starter and reliever depth. Once I had the players, I downloaded our Steamer and ZiPS projections, and calculated full-season equivalents to put players over the same denominators. Then I counted how many players are projected for a full-season equivalent of at least 1 WAR. This is the cutoff I used last year. I never love analyses that lean on these kinds of cutoffs, but I wasn’t too comfortable with anything else. The way I figure, a 1-WAR player isn’t great, but he’s useful in an emergency. It’s a player who can do some good.
In the plot below, you see every team in baseball, and how many total players project for at least that 1 WAR. Remember, bullpens aren’t included, because they’re annoying. Every team has a player or two you could quibble over, but even if the numbers aren’t perfect, the distribution here should be meaningful. A downside of this approach is it draws a huge difference between a 1.0 projection and a 0.9 projection. Another downside is it draws no difference between a 2.0 projection and a 1.0 projection. And, you know, there’s that word — “projection.” This is only as accurate as the projections are, and sometimes the projections just miss. There’s really no other way to do this, but if you have an issue with the forecasting systems, you’ll probably have an issue with this post.
But here’s the meat of the post. Put however much stock in it you want!
At first glance, maybe it’s a little dull — there’s no single dominant team, and there’s no single embarrassing team. The average is 18, with a standard deviation a little under 4, and the bulk of the teams are within spitting distance of the mean. But this is what most distributions look like, and there are still certain teams of interest in here. The first-place team has a total nearly twice as high as the last-place team. I get that the last-place team is the Phillies — but it’s also the Braves, and it’s also the Diamondbacks. Two of those teams are supposed to be bad. One of them wants to go to the playoffs.
There’s no questioning the top of the Diamondbacks’ roster. That’s the part that sizzles, and that’s the part that ought to be responsible for the majority of the Diamondbacks’ wins. But while theirs is a talented roster, it also looks like a thin roster, the starters flattening out after Robbie Ray and the hitters flattening out after, say, Welington Castillo or Nick Ahmed. There’s upside around, in the person of Jean Segura, or in the person of Yasmany Tomas, but last year they were replacement-level players. The Diamondbacks are going to need either great health or a handful of depth surprises.
Three other seemingly thin potential contenders: the White Sox, Blue Jays, and Marlins. This is the same issue the White Sox faced a year ago, and it hasn’t gotten all that much better. The rotation is going to need a big year from Carlos Rodon, and on the position-player side, one hopes they’re either right about Tyler Saladino, or Jimmy Rollins still has a little something left. The Blue Jays are also top-heavy, with things dropping off behind the roster’s front line. At least for them, unlike with the White Sox, the rotation might have six viable candidates. As for the Marlins, I can’t recall the last time they might’ve possibly been deep. They can’t afford depth, and they don’t develop depth. They wound up with just seven qualifying position players, and even the addition of Wei-Yin Chen leaves the rotation still shaky. Of moderate interest is that new pitching specialist Jim Benedict made a particular request for Edwin Jackson. Could be that’s something to watch. But the Marlins seem like they’ll need to stay healthy.
At the other end, the team leading the way shouldn’t be surprising. The Dodgers have prioritized depth and flexibility, that being their answer to losing Zack Greinke. Within a few months, the Dodgers could populate two full starting rotations. And the position-player picture is also deep, bolstered by players like Scott Van Slyke, Enrique Hernandez, Chase Utley, and A.J. Ellis. It’s like the Dodgers are anticipating injury problems, and while they might not ever strike, you can’t say they’re not prepared.
The Mets are also notable here, for all the depth they’ve managed to assemble. We all know how they’re going to have too many qualified starters once Zack Wheeler returns. They’re spoiled with their pitching riches, but it’s the position-player depth that could be a real difference-maker. I’m not even sure what they intend to do with Alejandro De Aza, but Juan Lagares is excellent insurance in the middle, and then there’s a host of players who can help out in the infield, which’ll be important given the issues surrounding David Wright. The Mets, like the Dodgers, seem prepared. Both teams are likely to need the support.
I don’t need to keep going like this. The Cardinals are always deep. Of course the Cubs are deep, on the field and in the rotation, and Joe Maddon might try to give some of his starters regular rest. The Rays basically always need to be deep, and the Indians are tied for being the deepest team on the position-player side. Anything to help them try to make up for the temporary absence of Michael Brantley.
It’s not a flawless method, but it’s a method, and there are your results. If some teams are lucky, they won’t need to call on their depth very often. That’s the thing about it — there’s no guarantee you’re going to need it. But should it become necessary, some teams are far better positioned than others. Perhaps the existence of depth reveals the depth of a plan.
Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.

This is neat! I think it could also be neat to see a breakdown of pitching depth vs positional depth.
Fun read, Jeff!
Would it make sense to do a average WAR of the same group of players. Depth is only part of it, high-upside talent is huge as well.
Depth is good, but it’s maybe just as (more?) important to have flexibility at the bottom of the roster to be able to replace underperformers with ease.
I’d say it’s better depth to have 4 or 5 optionable 0war projection guys in an even competition for a bottom roster spot then to have a 1war projection guy on a guaranteed deal big enough to mame you hesitate to drop if he’s flopping. You’d have better odds of finding a useful fill in that way, imo, especially since 1war projections are so flimsy in general. Team war projections would favor the team with the 1war guy but I’m not sure we should.
Depth is only good if you can use it.
Accessibility of depth is definitely one issue this doesn’t address. That stuff is so annoying.
I wonder how it would look if you calculated PA or IP given to players with less than a 1WAR projection. One thing I notice with these projections is that no one is projected for less than a 0 WAR, when in reality each team usually gives playing time to players with between -4 and -5 WAR (altogether).
For depth, wouldn’t Steamer600 be a better measure as it would handle having guys ready to come in under unexpected circumstances?
I agree with this.
To take it a step further, why not use the depth charts and Steamer600 to calculate the lost WAR at each position should the top guy get taken out, then average across the team? Maybe do it for position players and starting pitchers separately. You could also weight it by expected WAR without any lost players, so that you don’t just end up with good teams at the top of the list, which have more players further from replacement level.
I usually love Jeff’s articles, but it seems if this was the question he was trying to answer, the metric used was just a little too quick and dirty.
One thing that might differentiate teams further would be to add the projected WAR of the players that you calculate to have above 1 WAR (or 0 war or whatever). I would think that there is a big difference between having a 1.5 to 2 WAR backup for every position, and having a 1 WAR backup for every position…but this method wouldn’t show it.
Your introduction poo-poos the value of depth a bit. Not all depth is created equal, but the right depth can be a HUGE difference maker.
One common example is the 2013 Red Sox. That team was essentially baseball’s best from wire to wire, but it didn’t have much in the way of remarkable performances. For the most part, depth, across both the starters and the roster in general, was the team’s greatest strength. And people make the mistake of saying “everything went right” for that team, when in fact more when wrong than right. It was the depth that allowed the team to make it LOOK like everything went right, both to handle injuries and to take advantages of matchups while avoiding big drops when starters had days off.
Depth in this sense is more about how a team can recover from an injury to a starting player. It’s not about your #5 pitcher covering for your #2 pitcher’s performance any given week.
The major injuries the 2013 RedSox sustained were Bailey and Hanrahan, and that definitely uncovered a better closer/set-up situation in Uahra/Tazawa so they did exhibit some “depth” there. Overall that team’s success was more about multiple starting players over-achieving at the same time than it was about the last few guys on the 25-man roster.
Ohmygod shut up about the stupid 2013 Red Sox already.
Top 4 and bottom 5 are NL teams. AL is going to be so competitive this year.
I wonder if there is a way to incorporate positional flexibility into the depth considerations. Having a 1+ WAR player that can fill at several infield and outfield positions, or going two or three players deep in 1+ WAR players at each position would be better than having a collection of 1+ WAR players who can’t be moved around the field. This probably wouldn’t change the overall rankings that much, but it is another thing to consider.
For me, the foundational, must-read post on this subject is Jonah Keri’s study “What’s The Best Way To Build a Major League Baseball Team?:, posted on Nate Silver’s 538 blogosphere:
http://fivethirtyeight.com/features/whats-the-best-way-to-build-a-major-league-baseball-team/
Jonah sought to answer whether all-around balance teams are any better or worse than a “stars and scrubs” type team build. His initial finding was that neither model is superior, with maybe a slight edge to stars n’ scrubs. What’s far more important is the overall talent no matter how you assemble it.
That’s not quite the question Jeff was after but I feel it’s related. I think the takeaway is that hey, you do have 25 roster slots on your team, and with injuries and rookies pressing in, you wind up with some 30 – 40 players each year with MLB time. The depth pieces don’t play as much, BUT THEY DO PLAY. And those results matter, so improving your back-end depth is just another tool toward building a winning squad.
Maybe something to do is to try and do some visual representation of differences by color coding certain things? Say 5+ WAR is calculated by red, 3.5-5 WAR players color coded by blue, 2-3.5 WAR players by orange, and 1-2 WAR players by green (or whatever colors you want to use). It would be more time consuming, but might better allow readers to visualize the difference between a team like the Diamondbacks and the Phillies. Like, I don’t think the Diamondbacks are all that hot, but I don’t think they’re that bad, whereas the Phillies are going to be bad.
This would also create its own problems too, suggesting that the difference between a 3.4 WAR and 3.5 WAR player is large, when it’s really not, but as you’ve noted, you have to draw the line in the sand somewhere.
There is no reason you can’t have a more continuous spectrum of colors. For scientific figures, I’ll put a 100 colors ranging from red to white to blue. You just need to not do this in excel.
Have just completed an interesting study (which hopefully Fangraphs might publish) between the differences in composition between playoff and non-playoff teams since the start of the second wild card in 2012. “Depth” as defined in the above study (# players above 1 WAR) would not be a difference maker. The spread between a playoff and non-playoff team was 13 wins above replacement. But 10.5 of those wins (or 80% of the difference)were as a result of playoff teams having an average of 2-3 more players producing 3+ WAR than non-playoff teams. In fact, there was virtually no difference in the win totals generated by players with -.5 WAR to +1 WAR on playoff v. non-playoff teams. However, negative WAR players (-.6 or worse) were far more prevalent on non-playoff teams (on average they had 2 more such players) and they accounted for 1.7 Wins in difference between the average PO and non-PO team. This also makes sense as playoff teams typically trade to prevent further suffering at poor performing spots.
Except in exceptionally tight playoff races, it does not appear that having more marginal performers (i.e, those in 1-2 WAR category) is going to get teams over the hump, and that would be if such marginal performers were taking the place of negative performers.
would love to read this study. sounds right to me.
would love to also see some analysis as to whether those large negative slots on non playoff teams are more often due to being stuck with a contracted player flopping or due to just a lack of players with any track record for that slot.
So basically, teams with more good players make he playoffs. Teams with more negative value players don’t….
I hope you went into more detail. Stars and scrubs vs balanced. Pitching vs hitting. Which strengths (bullpen, power, Ks, contact rate, etc) correlate most.