Amazin’s hoping for the best with key cog in rotation

IT IS A fine line the Mets straddle now, as they dispatch Matt Harvey to St. Louis on Thursday. There, he will meet one of the top vascular doctors in the world in Robert Thompson.

And there, a still-vital piece of the puzzle of the 2016 Mets will seek peace of mind.

Understand: the Matt Harvey who goes on the 15-day disabled list, and will be checked for vascular issues and thoracic outlet syndrome, is nobody’s idea of a rotation savior. We have now seen enough of that version of Harvey to realize that whatever limitations Logan Verrett may have as a replacement, the gap between the two, right now, isn’t that wide, if it exists at all.

But that isn’t the version of Harvey that’s in question right now.

It’s the one who was so spectacular in 2013, and the man who returned from Tommy John Surgery in 2015 looking as if he hadn’t missed a beat, let alone an entire season. It was the one around which this season’s blueprints were drawn. But we haven’t seen that version since the ninth inning of Game 5 of the World Series. We have seen glimpses. We have seen hints. We have seen flashbacks.

Mostly what we’ve seen is an imposter wearing No. 33.

Now, Harvey flies to Missouri in search of answers, and the Mets are every bit as curious. Is the shoulder discomfort he experiences now to blame for what has been a harrowing first three months of 2016? And, more important to the Mets: Is it something that can be fixed in the short-term?

Because make no mistake: despite their recent offensive surge these Mets were built on the backs of their starting pitchers. That always included Harvey as an anchor, and even when he struggled it included the belief that once Harvey shook off his malaise he would return to the form he once knew, would be what the team expected he should be. Remember, though he may have been supplanted by Noah Syndergaard now, Harvey began this season as the team’s ace. You don’t just shake off losing your ace, even if he has been resoundingly vulnerable to date, even as the team has had to adapt around his struggles. The Mets were built on a staff. You remove a key element from that staff, you’re speeding toward a bad place.

So the Mets dance this odd dance: hoping an injury can be blamed for what has become of Harvey while hoping — maybe against hope — that said injury can be overcome in a matter of weeks, or a month. If not, that’s terrible news for a pitcher still two full years away from free agency. And worse news for a team that would suddenly be deprived of one-fifth of its core strength. They wait for news from St. Louis as the Nats arrive in town for four games that will go a long way toward defining who the Mets are, and where they are, at the season’s midway point. And also where they might expect to go in the second half

Hoping for hopeful news. Bracing for something else.