Recently, St. Louis general manager John Mozeliak was asked about his starting rotation in 2018. He said he was mostly content to go to battle with the players he had. Consider this, for example, from Ben Frederickson of the St. Louis Post-Dispatch:

Mozeliak says he's confident in the #STLCards rotation. Said a lot depends on how Waino looks. Carlos. Wacha. Weaver. Mikolas. Gant and Lyons could get in mix. "I feel like we are fine," pres said. — Ben Frederickson (@Ben_Fred) December 14, 2017

It’s unclear if there’s a design behind the order in which Mozeliak names the staff, but he does single out Adam Wainwright as a somewhat unknown variable.

Now there’s a rumor that the Cardinals are in on Jake Arrieta, which, especially when seen next to this discussion of pitcher roles next year, might mean that the 36-year-old Wainwright is losing his grip on his rotation spot.

As bad as last year was for the veteran Cardinal righty — and it was, since he was somewhere between the 18th-worst and 36th-worst starting pitcher who threw at least 120 innings last year — the way the season progressed may have been even more disheartening than even the overall results.

Take a look at the pitchers who lost the most velocity on their four-seam fastballs between the first and second halves last year.

Of the 584 pitchers who threw a four-seam fastball last year, Wainwright’s second-half velo would have ranked 19th worst in the group. In related news, he faced 116 batters in the second half and struck out just seven of them.

It’s possible that a return to the bullpen, where it all began for Wainwright, would make him an asset again. Most pitchers add around one-and-a-half ticks when they move to relief, and if he can average near 90 and throw a ton of curveballs, Wainwright might be a good sixth-inning bridge and a boon to the Cardinals bullpen a year after he was a weight around their collective neck.

That isn’t to say that Wainwright did not also leave a more positive legacy last year. The man with a vaunted curveball worked with 24-year-old rookie righty Luke Weaver and his hammer. Late last year the youngster described the pitch to me:

“The curve is a pitch I’m transitioning, I’m trying to use it in more aggressive ways,” Weaver said. “At first I was just trying to steal some strikes and get ahead, get it over the plate. Now I’m working that into how can I make this into a strikeout pitch. So I’m talking to Wainwright about what he’s doing in certain counts to make that an effective pitch.”

With his drop-and-drive, low-release-point delivery, Weaver may never have the curve that his mentor featured. But it does look like, in his last three games, Weaver found something that might be useful in the coming season: more horizontal movement.

Weaver’s Changing Curveball Pitcher Velo Drop Cut Early Weaver 80.0 -2.4 4.5 2014 Wainwright 75.4 -9.2 9.3 Late Weaver 79.6 -1.9 6.1 SOURCE: Pitch Info / Brooks Baseball Movement in inches, velo in mph.

By pitch-type values, three of Weaver’s four best curveball games came when he was throwing a curve that had more frisbee to it. A curve that looked like this:

As one pitcher ascends, another descends. Literally. Check out the pitchers that gained the most velocity on their four-seamers in the second half last year.

Most of the pitchers on this list moved into the bullpen in the second half, or had a major health event from which they were returning. And to be fair, Weaver himself may have just found good health late in the season, since he’d been dealing with a disc issue earlier in the year.

“I just have to stay on top of the exercises and the stretches,” Weaver said earlier in the year about his back.

That, and listen to his elders.