ARLINGTON -- The designated hitter was adopted by the American League in 1973 and ever since then, there has been a perceived difference between the National and American Leagues.

The stereotypical view is the American League has more offense while the National League has more strategy based on the fact that the pitcher has to hit. But Angels manager Mike Scioscia, entering his 14th season, doesn't see it that way from an offensive standpoint.

"The one thing I've found is there are many more things you can do on the offensive end with a DH in your lineup," Scioscia said. "In the National League, you find with the seventh or eighth hitter, moving a runner really doesn't make a lot of sense. In the American League, you can play little ball from the second inning if you want to from the bottom of your lineup."

Scioscia likes the idea of using the hit-and-run, the steal and the sacrifice bunt with any player in the bottom of his lineup without worrying about a rally being stopped by a pitcher with a .115 batting average.

"There are so many things that are opened up to your team to do with the DH that don't include the home run, includes a lot more of just playing baseball ... being able to do some things with the bottom of your lineup from the first inning on that just really doesn't make a lot of sense to do in the National League," Scioscia said.

That's just one of the adjustments the Astros and new manager Bo Porter will have to learn as they get ready for their first season in the AL. After 51 years in the NL, the Astros are moving to the AL West for the 2013 season. For the first time since three divisions came into play in 1994, the AL West will have five teams.

To this point, the AL West has been the exclusive province of the Angels, Rangers, Mariners and Athletics, making it the only four-team division in the game. It has also been one of the two most competitive.

Over the past 18 seasons -- taking away strike-shortened 1994 -- the Rangers, Angels and Athletics have each won five division titles, while the Mariners have won three. In the AL East, the Yankees have won 13 of the last 18 division titles. In the AL Central, the Indians have won seven titles, the Twins have won six, the White Sox have won three and the Tigers just two.

The only division that can match the AL West for even distribution of first-place finishes is the NL West, where the Giants and D-backs have won five titles each while the Padres and Dodgers have won four since 1995. The Astros won four division titles in the NL Central, second most behind the seven captured by the Cardinals. The Braves and the Phillies have won 16 of 18 titles in the NL East since 1995.

Now, the AL West has a new team ready to intrude on the competitive balance. There will be adjustments for everybody, from style to scheduling and travel.

"It's a different dynamic," Athletics manager Bob Melvin said. "It's a team that we don't know a whole lot about. They broke it down there over the last couple years and expect to get better going forward and probably have some resources to do it. You look at the record last year, I don't think that's going to be indicative of the type of team they are this year. It's a team that's probably going to be an up-and-coming team in the years to come."

The Astros enter a pitching-rich division. The AL has long been stereotyped as an offensive league, but not out West. Over the past four years, the four West teams rank in the top six among team ERA in the AL. The Rays have a 3.72 ERA over the past four years combined, followed by the Athletics (3.75), Mariners (3.86), Yankees (3.98), Angels (4.02) and Rangers (4.02).

"The pitching in the West is pretty tough, that's why the division is so tough," Rangers manager Ron Washington said. "Seattle, they've always played us tough because they've always had pitching. Oakland always has pitching. This past year they pitched, they had speed, they had many ways that they could hurt you and beat you in the ballgame, and they put it together.

"It is tough when you start to play in that division because you have to deal with good pitching."

The Astros do have to address the designated-hitter role for the first time, and they signed Carlos Pena earlier this month as their primary candidate. But having a full-time DH has become more of the exception rather than the rule.

Just in the past 10 years, only 35 times has a player had at least 400 at-bats in a season as his club's DH. David Ortiz did it eight times with the Red Sox and Travis Hafner did so four times with the Indians. Most clubs use multiple players as their designated hitter as a way of getting their regular position players extra rest.

"Unless you've got a guy that's thundering the ball and a guy who can hit for average and power and be a run-producer, it almost becomes a better situation for you if you can bounce it around a little bit, because you can give your guys a break," Mariners manager Eric Wedge said. "Obviously, you always want a hitter in that role. Maybe it's a guy that's your everyday third baseman or left fielder or whatever it might be, but you want to get him off his feet a little bit, but you still want his bat in the lineup.

"If you've got a guy hitting .300 and driving out 35, 40 [home runs] and driving in 120 [runs], that's great. But it's tough to find that."

The presence of the DH forces the AL manager to approach his pitching differently. In the NL, pitchers are often removed from a game simply because the game dictates a pinch-hitter for him. In the AL, pitching changes are all up to the manager.

"A lot of times in the National League, from a manager's standpoint, you get to that sixth inning, it's bases loaded, it's two outs, you feel like this is my best chance to get back into this game, and you're forced to hit for that guy at that time," Porter said. "In the American League, obviously, you're not dealing with that.

"You have the DH, the pitcher is not in the lineup. One of the things that we will stress to our starters is we're giving you the ball because we feel like you're one of the best five pitchers on this ballclub. We want them to take that responsibility quite seriously and not look over their shoulder at all."

If nothing else, the Astros must get used to the extra travel. The average distance between Houston and the five remaining NL Central cities is 1,120 miles. The average distance to their new four division opponents is 1,546 miles, which ranges from 241 miles to Dallas to 2,449 miles to Seattle. The Astros' shortest trip in the NL Central was 863 miles to St. Louis, while the longest was 1,366 miles to Pittsburgh.

The three AL West Coast teams are now looking at extra trips and extra time in Texas. It's a new setup for all involved.