If last season -- specifically, the latter half of last season -- is any indication, the Nationals have one of the better leadoff hitters in the game in Denard Span. Problem is, Span is recovering from his second surgery of the past four months (first it was a sports hernia procedure in December, and this week it was a core muscle surgery), and it could be four to six weeks before he's ready to resume baseball activities. Which means the Nats, for now, do not have one of the better leadoff hitters in the game.

So that's a bummer.

Particularly at a time when quality leadoff production is so scarce. In a perfect world, the guy at the top of your order would have Rickey Henderson-like speed, and maybe a little bit of pop, and it would be extra cool if he talked smack a la Willie Mays Hayes. But none of that stuff matters if the dude can't get on base consistently.

Last year, the Major League average for on-base percentage -- not just among leadoff hitters, but all hitters -- was .314. And yes, that even included pitchers at the plate, who are basically worthless.

You know how many teams got a .314 OBP or worse from their leadoff hitters? Eight! The Giants (.314), Braves (.314), Indians (.308), Mets (.308), Cubs (.303), Reds (.298), Padres (.292) and Mariners (.287).

If we elevate our expectations ever so slightly (and we might as well, as the OBP average for non-pitchers was .318), then we can toss in the Rays and Angels (both at .316) and say one-third of MLB teams spent the vast majority of their season stocking their No. 1 slot with a player who could not even exceed the league average at the simple task of, you know, not making outs.

That is sad, especially given all the emphasis so many organizations have placed on OBP, post-Moneyball.        

With all that in mind, let's take a look at the five clubs arguably best-positioned at leading things off and five expected contenders who, like the Nats, might have significant questions about their leading man at the moment.

In the Lead

Rangers: Shin-Soo Choo

Recognizing the rarity of positive production from the leadoff spot, the Rangers invested seven years and $130 million in Choo before '14. Some saw that as an insane sum for a guy who had never even appeared in an All-Star Game, let alone been considered for an MVP, and maybe, given Choo's serious slide in stats and health last season, those people were right. But PECOTA's projections, for one, are at least bullish on Choo in the OBP department in '15, predicting a .366 mark after he finished at .340 last year. That's actually the highest OBP among any projected leadoff hitter for '15, and I'm inclined to believe Choo's ability to read and work opposing pitchers has not disappeared.

Here's the problem for the Rangers: They had baseball's fifth-highest OBP from the leadoff spot last year, but their leadoff guy scored only 81 times. That is not a good ratio, and it's one a healthy Prince Fielder has to help correct.

Cubs: Dexter Fowler

Here, the Cubbies get the Most Improved award. Last year, their leadoff hitters -- mostly, a lot of Emilio Bonifacio and Chris Coghlan -- combined for just a .303 OBP with 85 runs scored. Fowler's arrival changes the equation completely. In 404 career games in the No. 1 spot, he has a .271 average and .366 OBP.

There is concern about his 67.1-percent career stolen-base percentage, so we'll see how much Joe Maddon pushes him. But, again, getting on base is the big key here, and Anthony Rizzo is suddenly in a much better situation to drive up his RBI total.

White Sox: Adam Eaton

Keeping this discussion in Chi-town, this is still somewhat more along the lines of a speculative status, as Eaton has yet to play a full season. But assuming he stays healthy, he'll be an OBP machine for a White Sox team with a ton of talent coming up behind him. Eaton had a .362 OBP in 123 games last year, and PECOTA projects a .349 mark and ZiPS a .354 mark for '15. He stole 15 bases last season, and it will be interesting to see how he develops as a baserunner.

But he's got extra-base ability, a little speed and the ability to get on base consistently. A lot to like.

Cardinals: Matt Carpenter

The Cards could have entertained the idea of Jason Heyward as their leadoff man, but a) he has zero interest in the role after his experience with the Braves and b) they're pretty well-situated, anyway. Carpenter doesn't have the speed you'd expect out of the leadoff spot (the Cards don't steal many bags, in general), but his discerning eye has allowed him to compile a terrific .379 career OBP, including a .375 mark last year. Nobody's scored more runs than Carpenter's 225 over the last two seasons. Not even Mike Trout.

St. Louis has entertained the idea of moving Carpenter down in an effort to improve an offense that sagged overall last season, but the plan for now is to keep that leadoff spot as is, and for good reason.

Astros: Jose Altuve

They dealt away Fowler, but the reigning batting champ (who posted a .377 OBP last year) is a pretty good backup plan for the Astros' leadoff slot. Now, granted, Altuve's batting average (.341) seems like it's going to regress, as it was propped up a bit by a .360 batting average on balls in play. Some might say the 56 stolen base total is due for similar regression.

But little go-getters like Altuve are hard guys to bet against, in general, and I don't think the drop in either total will be severe. He made major changes to his swing and his selection last year, and he deserves the benefit of the doubt as we see if those changes stabilize.

Worth noting: The Red Sox might have one of the best pure leadoff men in baseball in Mookie Betts, if he pans out as projected (PECOTA has him at a .356 OBP and 17 steals for '15). Problem is, at the moment, we're not totally sure if Betts will have a starting spot in the big leagues. John Farrell named Shane Victorino his right fielder until further notice (this is not a binding declaration, by any means), though Rusney Castillo is dealing with an oblique issue, which could open the door for Betts in center field. We'll see.

Leading Questions

Reds: Billy Hamilton

Game-changing speed is great and all, but there's that old line about how you can't steal first, and Hamilton got caught stealing 23 times in 79 tries last season. The jury's still out on whether Hamilton is an everyday player or a late-game bench threat. He got on base at just a .292 clip in his first full season. The Reds want to see him smack more line drives and slap more ground-ball singles and slash more bunt singles.

Basically, they want him to be a fundamentally different offensive player than he's been to date. 

Padres: Wil Myers?

We don't know who the Padres' leadoff man is, an especially interesting mystery in light of their heightened expectations for 2015. The Padres have loaded themselves with right-handed power bats, but they don't have an obvious candidate to set up RBI opportunities for that new-look middle of the order. It's possible Yangervis Solarte will settle in here, provided he settles in at third base. But he's battling Will Middlebrooks for that job, and, really, it's hard to know how much staying power either guy has at the moment (Middlebrooks obviously doesn't profile for the leadoff role).

Will Venable and Cameron Maybin are other options publicly discussed by Bud Black, but neither guy will have an everyday role if the outfield is healthy. So that leaves Myers as the best, most realistic option. Though he had a .354 OBP in his Rookie of the Year season in '13, Myers regressed to .294 last year. And both seasons were less-than-90-game samples. Myers did have a .389 OBP in his Minor League career.

Marlins: Dee Gordon

The Fish made great strides this winter to provide a versatile lineup around Giancarlo Stanton. But is it possible they weakened their leadoff spot? Not that anybody noticed, but they were actually pretty strong in the No. 1 slot with Christian Yelich last year, ranking fourth in the bigs in OBP (.346) out of the leadoff spot and ninth in runs (104).

Gordon is a step ahead of Hamilton in the whole "get to first before you can steal second" department, but how big of a step? Last year, his .326 OBP was significantly inflated by his strong April (.344/.375/.478 slash line). He had just a .300 OBP in the second half.

So Gordon is the Marlins' leadoff hitter for now, but we'll see if Mike Redmond shifts back to Yelich at any point in '15 if the offense isn't clicking.                                                                                      

Dodgers: Jimmy Rollins

In declaring Rollins his leadoff man last week, Don Mattingly said, "We don't truly have anyone else who fits in that role."

How's that for a ringing endorsement?

Rollins had a .323 OBP last year, and that was actually his highest in three seasons. So while the projections tend to love the Dodgers overall, this is one spot where they appear flimsy.

Mariners: Austin Jackson

If the M's are as good as people think they are, Jackson might prove to be one of the more important players in the AL. The Mariners significantly augmented the balance in the middle of their order with Nelson Cruz, but if Jackson repeats his disastrous post-trade showing at the plate (.267 OBP, .229 average), they're going to be scrambling, looking for a potential saving grace from the Seth Smith/Justin Ruggiano platoon or perhaps leaning on the winner of the Brad Miller/Chris Taylor shortstop struggle.

As manager Lloyd McClendon can attest from his Detroit days, Jackson has shown he can handle this role before. Just not lately. And a Mariners team that ranked dead last in leadoff OBP last year needs him to return to something more closely resembling his 2012 (.377 OBP) form.

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Anthony Castrovince is a Sports on Earth contributor and MLB.com columnist. Follow him on Twitter @Castrovince.