PORT ST. LUCIE, Fla. -- The New York Mets are the reigning National League champions, so the glass is definitely half-full.

Still, here are five reasons for optimism and five reasons for pessimism about the 2016 season.

Optimism

1. Stellar rotation: Is there a better five-deep rotation in baseball (six deep once Zack Wheeler returns from Tommy John surgery around July 1)? Matt Harvey will get Opening Day (or will he?), but as captain David Wright noted about the worthiness of any of the Mets’ starters to have received that honor: “Flip a coin.” Jacob deGrom already has earned an NL Rookie of the Year Award and an All-Star selection. Noah Syndergaard has dominated in spring training. Steven Matz is unbeaten in the regular season in his career. And Bartolo Colon keeps chugging along despite soon turning 43.

2. He’s back: The Mets were skeptical for much of the offseason that they had a chance to re-sign Yoenis Cespedes. But the slugger did, in fact, return -- at least for one season, after which he can opt out. The Mets became the first team in major league history to reach the World Series after ranking last in the majors in runs scored on July 31. That date, not coincidentally, coincided with Cespedes’ arrival in Queens.

3. Closer call: Yes, Jeurys Familia blew three saves in the World Series. But Familia really was unhittable down the stretch in the regular season for the Mets. After surrendering that demoralizing homer to Justin Upton in the rain on July 30, Familia did not blow a save the rest of the regular season. He went 16-for-16 in save chances, had a 1.23 ERA and .213 opponent batting average during that 30-appearance stretch.

4. We’re in the money: The Mets’ payroll is flirting with $140 million, a figure some fans might not have expected to see again after years of frugality. Yes, the Mets dumped Ruben Tejada during spring training in large part to save $2.5 million. But the money does seem to be there if the Mets need another jolt at this year’s trade deadline.

5. Deeper thoughts: The days of John Mayberry Jr. occupying the cleanup spot are over. Additions such as Neil Walker and Asdrubal Cabrera have given the Mets a legitimate lineup from the Nos. 1 through 8 positions. Is the lineup extraordinary? No. But it’s plenty good given the caliber of the team's starting pitching.

Pessimism

1. Aging captain: Wright missed four months last season dealing with spinal stenosis in his lower back. That issue has not gone away. It’s merely being managed and could flare up. Oh, and the captain is 33 years old now, too.

2. Defensive shortcomings: Mets catchers did not throw out a would-be base stealer during the entire postseason. And now the Mets are poised to see a ton of Cespedes in center field. Manager Terry Collins has even considered an alignment against left-handed pitching that places Juan Lagares in left field to allow Cespedes to remain in center.

3. Setup men: Addison Reed did OK in a late-inning role after arriving in a late-August trade with the Arizona Diamondbacks in 2015, but he struggled with inherited runners. And Antonio Bastardo's spring training struggles suggest he might not be an adequate replacement for the departed Tyler Clippard.

4. Washington gridlock: The Washington Nationals underachieved last season, but they still pose a serious threat to the Mets under first-year manager Dusty Baker. At least Cespedes balked on signing a five-year deal with the Nats that had significant deferred money. Daniel Murphy will bolster Washington’s lineup, though. And let’s just say Max Scherzer, Stephen Strasburg and Bryce Harper are formidable foes.

5. Hangovers? The Mets’ young pitchers logged a ton of innings last season. Harvey’s 216 innings, in fact, were the most ever by a pitcher in his first season back from Tommy John surgery. Will there be a hangover from that workload? Stay tuned.