In today's fantasy baseball environment, the most popular way for leagues to choose their rosters is to hold a mixed-league snake draft. However, this hasn't always been the case. The original incarnation of the game was to play in single-league (either American or National League only) auctions. The convenience of a snake draft and the preference to root for more familiar players has fueled the change.
While mixed leagues still dominate the landscape, there are nevertheless a significant number of fantasy enthusiasts playing in either American League- or National League-only single-league formats. What follows is a primer discussing the differences between mixed- and single-league formats. The focus will be strictly on league dynamics, although it is worth noting that mixed leagues mostly utilize snake drafts while single leagues are usually doled out via auction. Comparing and contrasting drafts versus auctions is a topic deserving its own discussion at another time.
Player Pool Penetration
The terms "shallow" and "deep" refer to player pool penetration. Mixed leagues are by their very nature shallow, since a smaller percentage of the available inventory ends up on active rosters. The repercussion of that is the non-drafted player pool in mixed leagues is far superior in terms of quality. As such, less patience is required in mixed leagues due tot he fact that the pool of viable replacements is far more robust. In single-league formats, the non-drafted players are almost exclusively backup catchers, milquetoast middle relievers and "bottom of the barrel" position players.
Pool penetration and the quality of the non-drafted players feeds into draft philosophy. In mixed leagues, taking risks is encouraged, as your bold moves are protected due to the parachute of a replacement pool. In single leagues, replacing an injured player or an overmatched youngster is far more difficult. The terms "upside" and "ceiling" are often bandied about in mixed-league analysis, while "reliability" and "floor" populate single-league jargon.
Steals and Saves
The main difference in rankings for single leagues is that stolen-base specialists and closers move up -- at least according to projected earnings. Of course, how you choose to handle drafting steals and saves is up to you.
Steals move up in deeper formats because the players who contribute stolen bases account for a larger percentage of useful steals in the draft-worthy player pool. The key here is "useful." A useful statistic is anything over and above replacement level, which in single leagues is extremely low for steals -- usually around just two and often lower. In other words, just about everyone expected to steal more than two bags are on an active roster, so fewer steals are subtracted from the player's total. In mixed leagues, the replacement level could be higher than 10, depending on the level of penetration. Because it's so hard to find non-drafted steals in-season, it's best to address the category in the draft or auction. Relying on a speedster like Mallex Smith or spreading them out over several hitters is a matter of draft philosophy. Both tactics have merits and pitfalls.
Saves are a little different. In a vacuum, the cost increases for the same reason as steals -- replacement level. However, even though single leagues are working with only half the teams, there is still ample closer turnover to supplement the saves category via in-season acquisitions. That said, the ratios for the elite closers are more beneficial in single leagues, contributing to their elevated ranking. The aggregate innings on a single-league staff are lower than those on a mixed-league staff so the ratios of elite closers exert more influence in single leagues.
Obviously, elite closer ratios also help in mixed leagues, but the numbers of innings pitched is bigger. As a result, the lowering of ERA and WHIP may not lead to your gaining as many points. Strategically, it's viable to funnel a lower portion of draft assets to closers in single leagues. You just have to realize that most of the saves available in-season come with baggage in the form of ratio damage.
Catchers and Positional Scarcity
Scarcity is a term used in all formats, and it comes in different forms. In single-league formats, it's in the ability of each team to field a legal roster composed of the best players and to not have to draft a lower-ranked player in order to meet a positional requirement. A hitting position short on draft-worthy talent is deemed to be scarce.
The test for scarcity is to rank hitters solely based on stats, with no consideration of position. Then, you count the number of players at each position and determine if there are ample players at each to legally populate every roster. It may take some juggling with multi-eligibility players and jumping between corner infield, middle infield and utility, but even in the shallowest of leagues, scarcity simply doesn't exist, except at catcher. About 10 years ago, the middle-infield spots were scarce in mixed leagues, but the influx of new talent (along with more players than ever qualifying at more than one position) eliminated this variety of scarcity for all non-catchers.
In just about all formats, even deep AL- and NL-only, catchers are scarce. The way to adjust was alluded to earlier: replacement level. The expected replacement-level contribution at each position needs to be subtracted from everyone at that position in order to yield useful stats. The production of a replacement-level backstop is markedly worse than the other positions, so fewer stats are taken away from catchers. (The stat line of the lowest-ranked draft-worthy catcher is worse than those of the other lowest-ranked position players.) However, the useful stats for each are the same since catchers lose less due to replacement. The upshot is that if a catcher and a hitter at any other position have the exact same stats, the catcher is the better fantasy asset. As an aside, the reason scarcity doesn't exist anymore among non-catchers is that the replacement level for all the other spots is about the same.
With respect to catcher ranking and pricing, the number of catchers needed in a lineup is crucial. Mixed leagues are split between needed one or two backstops. Single leagues almost exclusively require two catchers. The pricing bump from scarcity is greater in two-catcher formats since the replacement level is lower, as more catchers are on a roster. The bump lessens, however, as the pool penetration increases. Practically speaking, in single leagues with two catchers, receivers are projected to earn about $2 more than other positions with the exact same stats.
Strategically, there are more approaches in two-catcher, single-league formats. Do you draft two of the better options? Do you punt completely and choose from the end-game cesspool, churning until two adequate players are found? Do you elect to roster a pair of mid-level backstops? Do you draft one good and one bad catcher? There are multiple combinations to ponder.
Middle Relievers
In mixed leagues, unless the league rewards holds, middle relievers aren't especially useful. OK, maybe occasionally, it's better to float in a dominant set-up man instead of a highly unfavorable matchup with no better options. However, most of the time, a mixed-league's active staff will consist of only starters and closers.
In single-league formats, the elite middle relievers are often more useful than lower tier starters. Specifically, the wins and strikeouts recorded by poor starters aren't enough to overcome the mangling of ratios. On the other hand, dominant middle relievers can earn more points in ratios than they cost you in wins and K's. Drafting a middle reliever who logs the occasional save (or the "next-in-line" just in case their closing teammate falters) is a great tactic.
Reserves
As is the case with any format, know your rules. At this point, most single-league formats have reserve spots, with managers having the ability to freely move players between lineup and bench. Still, some "old school" leagues continue to restrict movement. This discussion assumes you do have the freedom to move between active and reserve spots.
In mixed leagues, most benches are designed to back up all the positions, with a couple of streaming pitchers and maybe a speculative closer. You don't have that luxury in single-league formats simply because the inventory to cover all your bases doesn't exist. You may be able to grab one or two position players with a chance to contribute, but the rest are mostly speculation. On the pitching side, if you don't draft a solid middle reliever or two, snagging them on reserve is crucial.
Again, know your rules! In many cases, there's still some open reserve spots. Sure, you can pick up a third catcher or a fifth outfielder, but if drafting prospects is allowed, consider stashing a youngster earmarked for their MLB debut. Yes, this is risky. They don't always pan out. However, the opportunity cost is next to nothing since they'll (hopefully) be replacing one of the worst batters on your team. If things don't work out, you can always cut bait and put an equally lousy player back in that roster spot.
Trading
There's a saying in leagues allowing trading: Draft stats, trade for balance. The notion is that you shouldn't worry about overloading on a category at the draft, since you have 26 weeks to maximize points. While this is still an effective ploy in single-league formats, realize that the level of wheeling and dealing likely falls short of a typical mixed league. There are a few reasons for this truth. In mixed leagues, a trade may leave you with a hole in your roster. Due to the lusher reserves and available free agents, you can "backfill" far easier than with the dregs populating single-league reserves and the non-drafted player list. In addition, it's harder to find a trade partner who is in sync with what you have to offer since it's tougher to build up a trade-worthy surplus in deep leagues. This doesn't mean you can't "bully stats" with the intent of dealing. You just need to be cognizant that the level of trading may be sparser than to which you're accustomed.
Free Agency/Waivers
The final topic is the difference with in-season player acquisition between mixed- and single-league formats. The use of FAAB (free agent acquisition budget) has permeated mixed leagues, replacing waiver priority. However, it's near universal that AL- and NL-only formats employ FAAB bidding, where the highest bid wins the player, losing that amount from their budget.
Single-league formats also need to ponder the approach for players crossing over from the other league. There was a time that avoiding players rumored to be dealt at the deadline was a cogent strategy, but most single leagues have changed their rules to allow teams to continue to earn stats from players moving to the other league. Again, know your rules.
Deciding whether or not to "nickel and dime" early-season bidding, hoarding ample budget to be in on the difference makers entering the league later on is key. Of course, you're risking the chance that few suitable players actually get dealt into the pool, but fantasy leagues can be won with a deadline deal pickup. However, failing to satisfactorily address deficiencies early on could render catching those big fish moot. Not to mention, hitting on an early pickup means more transaction periods where you accrue stats. More often than not, this decision is dictated by your team's plight. That said, if bidding early is called for, the optimal approach is to get your guy. Don't worry about overbidding. Once you're out of the running for a crossover player, make sure you get the cream of the early crop.
Speaking of which, ball clubs are advancing prospects sooner than in the past. Depending on the league rules, there could be an influx of talent in late April and again when the Super-2 deadline has passed. Instead of miserly holding firm to your FAAB for the end of July, picking up promising rookies is the new "having the hammer for crossover players."
Summary
There's a myth that mixed leagues are less challenging than in single leagues. They say it's like comparing checkers to chess. The truth is, though, the quality of league managers always dictates the competitiveness of the league -- not the penetration of the player pool. That said, those making the transition to single-leagues should be aware of the differences in player valuation, risk management, draft philosophy and nuances of in-season management. Don't be daunted by the perceived depth of single leagues. Knowing the Triple-A stats of the 26th player on major league rosters can enhance your appreciation for the game. After all, isn't that what playing fantasy sports is all about?