Faith or doubt in D.C.? Baker could be sweet for Nationals, but ...

Should Nationals fans be optimistic or pessimistic? New skipper Dusty Baker knows how to turn teams around, but can Ryan Zimmerman & Co. stay healthy after a lost 2015? Getty Images, USA TODAY Sports

The Washington Nationals are expected to duke it out with the New York Mets again for bragging rights in the NL East. There’s plenty of reason to think that, after a disappointing second-place finish last year, they’ll come out on top this season. Of course, there’s also ample evidence that suggests they won’t.

Here are the top three reasons Nats fans should be optimistic heading into 2016, along with three reasons they shouldn’t. This being baseball and all, let’s call it three up, three down:

Three up

1. Manager matters: When it comes to turning around big league ballclubs, new skipper Dusty Baker has been there, done that. In three previous managerial stints with the Giants, Cubs and Reds, his teams have improved by an average of 18 wins in his first season. A dozen and a half more victories on top of last year’s total would give Washington 101 wins this year. While that might not be a realistic projection, it’s entirely reasonable to expect the laid-back and experienced Baker -- whose 1,671 wins are second among active managers -- to be a difference-maker in D.C. For what it’s worth, a year after going 11-16 in Grapefruit League action, the Nats have already surpassed their win total and have a record among the best in baseball this spring.

2. Balanced bats: Last season, the overly right-handed Nationals, whose only lefty-hitting regular was Bryce Harper, were three games under .500 against righty starters (60-63) compared to seven games over .500 against southpaws (23-16). The addition of lefty contact hitters Ben Revere and Daniel Murphy should make Washington better against right-handers. The presence of Revere and Murphy, who last year had the lowest and seventh-lowest strikeout rates in the majors, respectively, should also help the Nats cut down on their 22 percent team whiff rate, which was third highest in the NL.

3. Bottom-feeders: The Braves and Phillies aren’t the only National League teams that appear to be tanking, er, building for the future, but they very well might be the most committed to that agenda. In other words, don’t be surprised if Atlanta and Philly end up with the two worst records in baseball. In theory, because the Nats and Mets will play both those teams the same number of times (38 games), it should have no effect on who wins the division. But relative to teams in the Central and West, a feast on the least of the East could give the Nats a leg up in the wild-card race -- that is, if they don’t win the division outright.

Three down

1. Arm uncertainty: Every rotation has question marks on the back end. That’s why it’s the back end of the rotation. The Nationals are no different. Former first-rounder Joe Ross excelled as a rookie but ran out of gas in September and has never thrown more than 153 innings as a pro. Tanner Roark won 15 games in 2014, his first full season as a starter, but struggled last year after being bumped to the bullpen. If either (or both) has trouble this season, Washington will be hard-pressed to keep pace with the Mets.

2. Unproven pen: The Nationals’ bullpen has more unknowns than an algebra textbook: Four members of last year’s pen are gone after an offseason in which the club acquired Oliver Perez, Shawn Kelley, Yusmeiro Petit and Trevor Gott. Holdovers Blake Treinen and Felipe Rivero have quality stuff, but neither has much experience. In other words, bridging the gap between the starters and closer Jonathan Papelbon could be a challenge.

3. Durability doubt: First baseman Ryan Zimmerman, who has hit more homers than anybody in a Nats uniform, is supposed to be the team’s cleanup hitter and the main source of protection for Harper. But in 2015, plantar fasciitis limited him to 95 games, the second straight season he played in fewer than 100 contests. This spring, Zimmerman didn’t appear in Grapefruit League play until March 13 and hasn't taken the field for a large portion of Washington's games. Baker has said he’s merely being cautious with the 31-year-old slugger, but anyone who’s ever dealt with the dreaded PF knows that it doesn’t go away quietly. Add to that concerns about left fielder Jayson Werth (203 games missed in the past four years) and third baseman Anthony Rendon (82 games missed in 2015), and health could be a major factor.