Jacob Arrieta's arrival to the Phillies makes the National League East more interesting and more competitive. Even better, the division was already trending rapidly in that direction.
Are the Nationals still a lock to win it? Yes, probably so. They remain, top to bottom, as good as any team in the game. Until the very end, some of us thought Arrieta would have been a perfect fit for Washington.
Arrieta's stuff has regressed some in recent seasons, but he's smart enough to make the kind of mid-career adjustment that the special ones are always able to make. In the past five seasons, he is 36 games over .500 at 69-33 with a 2.86 ERA, a 1.055 WHIP and a 140 ERA+. Arrieta has averaged 165 innings per season and compiled a 3.08 ERA in nine postseason starts.
To line up Max Scherzer, Stephen Strasburg and Arrieta for a postseason series would have made the Nationals a frighteningly good October team. They're frighteningly good anyway, but you know what I mean.

Back to the NL East. This division suddenly is interesting. The Mets certainly could push for a postseason berth, and the Braves and Phillies are rapidly turning the corner.
In fact, Atlanta and Philadelphia probably are the teams to watch this season, as young players get their chance and figure things out. One thing we've learned from the Royals, Cubs and Astros in recent seasons is that young players don't come with timetables. They shouldn't come with ceilings on their expectations, either.
So here goes:
1. Nationals
Same old, same old. Bryce Harper once more looks like the NL's best player, Scherzer is Scherzer and Tanner Roark and Erick Fedde give the rotation nice depth. Best of all, that bullpen -- the one that caused such angst in recent years -- could be one of the NL's strongest. Dave Martinez has stepped into a nice spot for his first managing gig, and he's certainly capable of taking things the rest of the way.
:: Spring Training coverage presented by Camping World ::
2. Mets
They have some significant question marks. Noah Syndergaard, Jacob deGrom and Robert Gsellman have given the Mets reasons for hope, and Matt Harvey has mostly thrown the ball well. Center fielder Brandon Nimmo is forcing his way into a lineup that looks plenty good enough after the additions of Jay Bruce and Todd Frazier.
3. Braves
If not a perfect spring, pretty close to it. Outfield prospectRonald Acuna Jr., hitting .433, is on his way to being one of baseball's next great players, second baseman Ozzie Albies has been very good, and the rotation appears to have a formidable front three in Mike Foltynewicz, Brandon McCarthy and Julio Teheran. Acuna may not make his Major League debut until June, but whenever it happens, Atlanta will celebrate.

4. Phillies
Arrieta's professionalism, work ethic, poise and raging competitive fire are a perfect fit for a young team that appears to be capable of turning a corner in 2018. Those young starting pitchers could not have a better role model. Now we get to watch left fielder Rhys Hoskins, right fielder Nick Williams and shortstop J.P. Crawford attempt to figure things out in a lineup with newly signed first baseman Carlos Santana. This ultimately will dictate how quickly the Phillies compete.
5. Marlins
This team is more of an unknown quantity than any other, except possibly the Rays. Manager Don Mattingly is going to pencil Lewis Brinson into his lineup in center field and watch one of baseball's most interesting prospects create some excitement. Dillon Peters and Sandy Alcantara are also prospects to watch at the back of the rotation.