These 10 things have changed division races

The D-backs are cruising along with the National League's best record. File that one under "pleasant surprises," which is not to be mistaken with "jaw-dropping, forehead-slapping stunner."
We've had some of those. You might have thought the Mets, Phillies and Braves would be interesting, but you probably didn't have them all ahead of the Nationals as we reach April's final weekend.
Did you have the Cardinals, Brewers and Pirates leading the Cubs? Don't even think of trying to sell that one. If we're really lucky, these opening few weeks are a preview of a season that could be a wild ride.
How did we get here?
Let's look at 10 things that have changed the races:
1. The D-backs had a very good pitching staff in 2017. They're even better in 2018.
Arizona's 2.92 ERA is the best in the NL by a wide margin. Newcomers Brad Boxberger and Yoshihisa Hirano have been added to the bullpen, and Patrick Corbin, Zack Godley and rookie Matt Koch have been strong in leading the rotation. If Zack Greinke and Robbie Ray get going, this group could be scary good.

2. The Red Sox envisioned Chris Sale, David Price and Rick Porcello leading the way in 2017. This season, they're doing just that.
Price and Porcello never got going last season for different reasons. This season, they're both healthy and confident, and with Sale as good as ever, the Red Sox may be the only team that can match up with the top of Houston's rotation.

3. The Braves already had the NL's best offense, and now Ronald Acuña Jr. has been added to the mix.
Offensively, they're scoring a little more than one run per game more than they did in 2017. They get on base, hit the ball in the gap and steal bases. Second baseman Ozzie Albies is off to an MVP type of start, and third baseman Ryan Flaherty has been a great under-the-radar addition. Into all this fun steps Acuna, baseball's No. 2 prospect.

4. The Swingin' A's are back in business, and Jed Lowrie is producing like a serious American League MVP candidate.
The Athletics have been a different offensive team since third baseman Matt Chapman and first baseman Matt Olson joined the lineup last season. Left fielder Khris Davis is also part of these new bash brothers. If there's enough pitching, the A's could make things interesting in the AL West.

5. The Angels have checked off all the boxes: healthy rotation, deeper lineup and a unique rookie.
They didn't have any of those things last season. Garrett Richards and Tyler Skaggs are healthy, Zack Cozart and Ian Kinsler have been added to the lineup, and Shohei Ohtani is the most interesting rookie baseball has had in a long time.

6. The Mets finally may be who we thought they were. That rookie manager hasn't done too shabby, either.
It's not just one thing. It's a healthy Noah Syndergaard. It's Zack Wheeler taking a step forward. It's Todd Frazier and Michael Conforto in the same lineup. And it's the new manager, Mickey Calloway, preaching the power of positive thinking.

7. The Cardinals are pitching like a championship-caliber team, and all the other questions could be small ones.
The rotation is roughly one run per game better than last season, and with a true ace in Carlos Martínez and Adam Wainwright back in the saddle and Jack Flaherty fulfilling his promise, the Cardinals look like a team that could be formidable all summer long.

8. The Phillies have the look of a team with almost no weaknesses, and the NL East could be crazy entertaining.
They added Jake Arrieta to the front of their rotation, and that takes some of the pressure off the excellent young starters. Rhys Hoskins is an on-base machine, continuing to build on what he started at the end of last season, and center fielder Odúbel Herrera continues to get better and better.

9. The Brewers surprised plenty of people last season, and they're even better -- and surprising no one in 2018.
How do you build a great pitching staff without busting a budget? You add right-hander Jhoulys Chacín and watch him continue the roll he started with the Padres last season. You add another veteran, Matt Albers, to your bullpen, and even with closer Corey Knebel on the disabled list, your bullpen is lights out.

10. The Blue Jays made a bunch of changes, and when they get their best player back, the AL East could have another team bunched at the top.
Right-hander Aaron Sanchez is healthy, and as soon as third baseman Josh Donaldson is back in the lineup, the Blue Jays could have a nice run in them. Adding veteran outfielder Curtis Granderson has been a stroke of genius by general manager Ross Atkins.