Adam Wainwright's tank was nearly empty, yet batted in the sixth and remained in the game for the seventh

Ten years into his MLB career, Adam Wainwright has proven to be a bona fide ace and will go down as one of the best pitchers in the rich history of the St. Louis Cardinals. That being said, in Monday's home opener against the Milwaukee Brewers, manager Mike Matheny had a chance to set the tone for the 2015 season by removing his ace (for a pinch hitter with one out in the bottom of the sixth) despite the fact that the team was still within "striking distance" (i.e. down by only one run) for a starting pitcher win. Sure, Wainwright had thrown only 83 pitches up to that point, but he was on the verge of turning the Milwaukee lineup over for the fourth time—which is never a good sign with nine outs still to record—and he wasn't exactly in cruise control mode.

A closer look at the PITCHf/x data (via BrooksBaseball) paints a pretty clear picture of the events that transpired:

Velocity graph

Of course, it is not unexpected for a pitcher's velocity to decline as the game goes along. However, what we see with Wainwright in Monday's outing is a steady downward trend starting much earlier in the game than what is desired—as early as the 40th pitch of the game. Two starts into the 2015 season, is this a cause for serious worry? Probably not, but as the ace of the pitching staff, it is definitely something worth watching as the season progresses.

As I stated before last year's NLCS game 5 against the San Francisco Giants, "Waino is at his best, [when] he's painting corners, both up and down, with his fastballs (fourseamer and sinker), setting up two-strike cutters off the outside corner or devastating Uncle Charlie's in the dirt." Of course, despite my immense worry, Wainwright took the mound and hurled a stellar, seven-inning performance. A huge reason behind his success was his use of the fourseamer (36 times) and sinker (12 times) to set up his breaking pitches.

Horizontal pitch location (non-pitcher at bats only)

First and foremost, given the state of Wainwright's repertoire (i.e. he isn't blowing hitters away anymore), it is a good to see that only 9.9% (9 of 91) of his pitches were over the middle portion of the plate on Monday. However, what is not ideal about his pitch location is the fact that he basically lived on the outside part of the plate at 63.7% (58 of 91). This leaves only 26.4% of his pitches on the inner half, and upon further review, only 12 of those 24 were either fourseamers or sinkers—the two pitches that most effectively set up his curveball and cutter.

One at bat in particular explains Wainwright's seventh inning on Monday evening: the RBI double by center fielder Carlos Gomez that extended Milwaukee's lead to two instead of one. This was the fourth time Wainwright had to face the dangerous leadoff batter. Now, to be fair, according to Baseball-Reference, Wainwright has been most effective against hitters the fourth time through the order (or later), and this is something Ben touched on when looking at overall league numbers last February.

Ben's survivorship bias theory makes a lot of sense regarding overall league success. However, what I would like to add, specifically focusing on Wainwright, is that more often than not, when Waino faced hitters for the fourth time in a game, it occurred in innings later than the seventh because he was cruising along, with a repertoire in full swing. For whatever reason, this was not the case Monday afternoon/early evening, and it was pretty clear for those who have grown accustomed to Wainwright's way of pitching over the last 10 years. Let's now look at the details of the previously-mentioned Gomez at bat:

Pitch sequence: Cutter (87.8 MPH), Curve (77.4 MPH), Cutter (87.8 MPH), Curve (77.0 MPH)

Pitch location: Down and outside, down and outside, down and outside, down and outside

via @ThePitcherList

Focus on the glove of Yadier Molina. Despite the count being in his pitcher's favor, he knew the curve was a vulnerable hanger, and though not legally possible, it's almost as if he made a pronounced attempt at reaching out for the ball hoping to get to it before Gomez's bat could. Piggybacking off my pitch location discussion from earlier, Gomez faced nine pitches from Wainwright on Monday and seven of them were located down and outside. While Waino's curveball and cutter are effective pitches for him, a good hitter like Gomez can time them up if he knows they're coming and has a general idea of their location.

Bottom line

Wainwright has been a near-Cy Young Award pitcher in his career because he has four pitches he can use and locate at basically any time. Unfortunately, we did not see this level of pitching from Waino during the home opener. Fortunately, he is one of the best at being effective even when his stuff isn't as sharp as he would like. There was an opportunity to remove him before additional damage was done, but he remained in the game, the Brewers increased their lead to three (5-2), and the Cardinals offense failed to push one more run across to tie the game, ultimately losing 5-4.

While Wainwright isn't entirely on board with the idea, Monday's game was a perfect opportunity to limit a high-stress inning from Wainwright's valuable right arm. Not only would the ace have benefited from a shorter-than-normal outing in terms of pitch count (83 pitches), but a fresher and possibly more effective reliever could have pitched the seventh. For all we know, this reliever could have come into the game and allowed five or more runs, but the point is Wainwright didn't have his best stuff from the very beginning and his velocity was dropping significantly to the point where his cutter's velocity was virtually the same as that of his fastball (87.3 MPH versus 87.9 MPH, respectively).

Of course, not much can or should be made about one start in the month of April, but a few things to keep an eye on going forward are Wainwright's fourseamer and sinker velocity (throughout the game) along with his horizontal pitch location. If he is sitting in the 91-92 MPH range and consistently working both sides of the plate, the Cardinals will be in good shape. If not, the situation will have to be addressed further.

Credit to BrooksBaseball for the PITCHf/x data and @ThePitcherList for the GIF.