The lines between the American League and National League have blurred considerably in relatively recent years.

Beyond the fact that the AL and NL face each other during the regular season, some other systematic changes have been put in place. Where the two sides once alternated picks in the First-Year Draft, they now have their selections dictated solely by final record, regardless of league. Where AL umpires and NL umpires were once separate bodies, the men in blue now navigate from one league to another all the time. Even the league presidents have become ceremonial figureheads.

So as baseball's evolution continues, it's fair to wonder whether the league lines have blurred to a point where they ought to be disintegrated altogether?

In other words, is it time for the AL and NL to play by the same rules?

That's a question that's come up quite often in the wake of the news that MLB will level out its leagues in 2013. When the Astros move to the AL West, each league will have 15 teams, and that will provide better balance in terms of scheduling and, therefore, more fair competition for a playoff spot, particularly with another Wild Card added to the mix in each league.

It also, however, will mean that at least one Interleague game will have to be played every single day of the schedule, including Opening Day and the last series of the season. And to some, this reeks of reason to finally, once and for all, make the designated-hitter rule the same for both leagues, across the board.

"I think, at some point, it's going to come to pass where there's either going to be a DH or no DH," Tigers manager Jim Leyland said. "I think that's going to happen at some point."

Leyland is a member of Commissioner Bud Selig's committee for on-field matters, and he's a well-respected voice in the game. But if the commissioner's recent statements on this matter are any indication, the current DH disparity isn't going anywhere.

"I think it's fine [as is]," Selig said last month. "I'll say this, it doesn't bother our fans. It'll take some big event to move either way."

It would take a big event, because the simple fact is that while some of the differences have diminished and the advent of Interleague Play in 1997 tore down the wall between leagues, strong proponents of both models remain.

On the one hand, you have the purists. Those who sympathize with the strategy that comes with having pitchers bat. The double-switches and pitching swaps based upon that spot in the order and the benefits of a deep bench.

On the other, you have those who yawn through a punchless pitcher's putrid at-bat. Those who want more offense and those who want to see starters go as deep into the game as their arm and effort allows, without having their outing compromised by the need to bring in a pinch-hitter for their turn in the order.

It's long been a great debate in the game.

"The sentiments are so strong for both leagues," said Indians general manager Chris Antonetti, "that I'm not sure we'll ever have a consensus on it."

Still, a consensus could become conceivable when the Interleague action is stretched out over the long haul and not in a short summer spurt.

Understand, first of all, that nobody is anticipating a 2013 schedule in which there is a radical rise in the number of Interleague games. Currently, clubs play between 15 and 18 such games. Most play 18, but because there are six teams in the NL Central, those teams play three less than the rest.

It is anticipated that 18 will remain the target number after the Astros move. That would continue to mean nine games for each club under the other league's rules.

Now, for some, this is cause to rejoice. AL clubs have long complained when they have sustained stretches of six or nine games in NL cities -- a significant period of time to be without your DH. And by the same measure, NL clubs not fully equipped to fill the DH role have endured similar difficulty.

With the nine games spread out over six months, that will no longer be an issue.

But the flip side to the argument is the concern over Interleague games being played in the home stretch of the season, when pennants and postseason spots are on the line. After all, is it fair to rob an AL team of its DH on the final day of the season, if it's a win-or-go-home scenario?

Certainly, the three other major sports -- the National Basketball Association, National Hockey League and National Football League -- all have their teams intermingle between conferences for the full course of the season, but none of those sports have fundamentally different rules for each conference.

"The [American Football Conference] doesn't play with different rules than the [National Football Conference]," Leyland said.

Maybe the "big event" that prompts a change will simply be an accumulation of club complaints, should the above scenario come to fruition. Only time will tell.

For now, though, the game has its share of folks on both sides of the argument. Those in favor of stability and those in favor of synchronization.

"Personally, I kind of like it [the way it is], from a fan's perspective," Rangers GM Jon Daniels said. "It's one of the unique things about the game. Two different sets of rules. No other game is played that way. I understand that's also the reason other people don't like it, but I don't think it's that dramatic when you're only playing nine games a year with the other team's rules. Personally, I don't see a big issue with it."

Said Padres manager Bud Black: "I'm a proponent, I think eventually, of seeing things standardized."

The key word is "eventually," because there is current curiosity over how the new schedule will affect not only in-season strategizing but preseason preparation and club construction, as a whole.

"The big challenge of that is going to be your pitchers, preparing them," Orioles manager Buck Showalter said. "One of the things about the American League and the Interleague is you've got that period where you get everybody acclimated. Now, all of a sudden, how do you do that? I'm anxious to hear some of the hitting coaches and pitching coaches' ideas on that, because it's going to be jagged. The last thing you want to do is get a pitcher hurt through that process."

AL clubs will have to have their pitchers take batting practice in Spring Training, particularly if they have Interleague games on the early season schedule.

"In the past," Indians manager Manny Acta said, "you could relax and wait until May or June."

And the change also has the potential to impact the way AL clubs plan for and utilize the DH position. It's no secret the position has evolved quite a bit in recent years, to the point that the "traditional" full-time DH who doesn't even own a glove -- the David Ortizes and Travis Hafners of the world -- has become something of a dinosaur.

Teams value versatility and the ability of using the DH spot to give guys a break from the field while preserving their bat in the lineup. You could see an increase in that line of thinking come 2013 and beyond.

"It could be good for the game," Mariners manager Eric Wedge said, "because the kids are going to have to have more knowledge about what's going on. When you bring a guy like Jamey Carroll over from the National League to the American League, he watches the game a little bit differently because he's been involved in that. I think, in that respect, it could be good for the game."

But if the Leylands of the world ever get their wish and the league rules have harmony, which format would be best for the game?

To DH or not to DH? That is the question.

No matter your sentiments, it's safe to assume the DH would win out in that argument. That's because it would have to be collectively bargained with the players' union. And where there's a DH, there are more jobs to be had and more money to be made.

"There's a lot more at stake with the DH," Antonetti said. "Jobs, dollars. The DH is one of the highest-paid positions still. And the leagues have been operating independently for so long that I don't think there's ever going to be a consensus."

So in absence of consensus -- and likely for the foreseeable future -- we'll continue to have what we have now.

Two leagues. Two rules. And two distinct opinions on what is right and what is wrong with regard to the DH.