clock menu more-arrow no yes mobile

Filed under:

One game, one starter: Flaherty or Mikolas?

Assuming the Cardinals make it to the promised land, who might they turn to with everything on the line?

MLB: Milwaukee Brewers at St. Louis Cardinals Jeff Curry-USA TODAY Sports

Optimism is an important feature of a healthy baseball fan. While it can lead to devastation, it prevents one from succumbing to a negative attitude in situations where pessimism isn’t productive.

The Cardinals play one game against the Brewers tonight before heading to Chicago for three against the Cubs. They sit one-half game back of the second National League wild card with divisional hopes secondary. If they can claw past the Rockies, or whichever National League team ends up failing to overcome the other, one game will be the difference between going home and the playoffs. (There is a chance for a 163rd game to decide the teams in the play-in game, but let’s focus on simplicity for this exercise.)

In the event the Cardinals find themselves in a winner-take-all battle—optimism!—the starting pitcher toeing the rubber means a lot for the Redbirds’ chances.

At the moment, Miles Mikolas and Jack Flaherty are scheduled to start each of the last two games of the Cardinals season. This takes away Shildt’s two strongest options for the wild card. While we can speculate on the options that aren’t Flaherty or Mikolas, I wanted to dream up a scenario where Shildt was able to decide between the two starters in a must-win game.

Even if this comparison goes to waste if the duo starts Saturday and Sunday, hopefully it will provide some perspective on each pitcher’s strengths as they head into what could become a pair of must-win games. Regardless of rest, the comparison can also be used for a scenario in the playoffs where Shildt needs a win from a starter.

Plan of attack

Mikolas and Flaherty are very different pitchers in how they generate positive results. Mikolas is a four-trick pony, mixing a fastball, slider, two-seamer, and curve all between 20 and 27 percent of the time according to Baseball Savant. He has a tendency to break out his curveball more versus left-handed hitters, and his slider versus right-handed hitters which expands and contracts the usage window mentioned.

His curveball’s shape lends itself to more contact than swing-and-miss, with vertical break towards the top of Pitchf/x leaderboards. His slider is harder than average, another contributor to contact over swing-and-miss, and doesn’t stand out in terms of movement either vertically or horizontally.

Mikolas locates exceptionally well, holding the lowest walk rate in all of baseball among qualified starters (3.7 percent). He isn’t overpowering, evidenced by his sub-20 percent strikeout rate and tendency for ground-ball contact. His reliance on an average Cardinals defense to back him up has allowed him to put together an exceptional season.

In a one-game battle, Mikolas is going to mix everything together, as he has done all season. He’s going to be efficient with pitches, generate a lot of contact and in a good scenario take the Cardinals into the sixth inning with 1-2 runs on the board and nothing more. There is a chance he dominates, but the expectations are to keep the Cardinals in the game and remove burden from the Cardinals mediocre bullpen if he needs to face the opposing lineup a third time.

Flaherty is a different animal. He mixes a fastball, two-seamer and slider against right-handed hitters with emphasis on his slider. The curveball that led somewhat to his breakout is brought into the picture versus left-handed hitters as he adds emphasis to his fastball.

His swinging strike rate would place him inside the top ten pitchers in baseball if he was considered a qualified starter, a stark contrast to Mikolas’ contact-heavy, ground-ball approach. This is primarily due to his premiere offering, a slider that possesses a top-10 whiff rate among pitchers with 200 or more sliders in 2018. The pitch’s depth is exceptional, moving above average both laterally and vertically in a lower velocity band than the average slider in baseball. His location of the pitch this season has been consistently at the bottom of the zone, limiting damage when the pitch is not tailing off the plate in a two-strike count.

The knock on Flaherty is the lack of a good third pitch. His curveball and changeup are both average, but oddly enough he doesn’t possess massive issues when he faces a lineup for a third time in one game. He does get slightly worse, but compare this to Mikolas and you’ll see some deterioration versus a plateau.

Slash line each time through order, 2018

Flaherty’s success is going to be dependent on the feel for his slider and ability to get ahead with his fastball, a more traditional path to success that is mentioned with numerous pitchers almost all the time. This attack also shows up in his Baseball Savant breakdown of how he approaches hitters. His upside is higher than Mikolas’, but he possesses a higher risk for bottoming out if he lacks feel on his fastball or slider out of the gate.


Below is each pitcher’s performance this season versus some of the teams likely opponents down the stretch.


  • CHC - 3 starts, 18 IP, .271 average against, 12 K, 3 BB
  • LAD - N/A
  • COL - 2 starts, 11 23 IP, .380 average against, 9 K, 2 BB
  • MIL - 4 starts, 22 23 IP, .240 average against, 22 K, 2 BB


  • CHC - 2 starts, 10 IP, .121 average against, 16 K, 7 BB
  • LAD - 2 starts, 12 IP, .125 average against, 18 K, 4 BB
  • COL - 1 start, 5 13 IP, .238 average against, 7 K, 2 BB
  • MIL - 4 starts, 23 13 IP, .173 average against, 34 K, 8 BB

There isn’t much here that should sway opinions one way or the other. Mikolas’ pitched one game in Coors, which will naturally inflate numbers against him given how often contact generally results in damage. The most encouraging point here is how successful each arm has been against the Brewers this season, a likely opponent if the Cardinals push out the Rockies.

The Dodgers offense is one of the best in the National League, especially given their production against sliders, which would limit the effectiveness of Flaherty’s and Mikolas’ best pitch. The easiest opponent for the Cardinals—and unfortunately the least likely—is the Rockies, while the Brewers and Cubs remain close on a variety of offensive statistics.

The decision

A variable in this decision is how comfortable Shildt is matching up bullpen arms with either team’s lineup late in the game. The advantage with Mikolas is that if the Cardinals experience heavy usage of relievers over the weekend in Chicago, there is a good chance he can survive later in the game, even if it means giving up 3-4 runs.

Flaherty can survive late in the game too, limiting the need for bullpen usage, but the chances of a vintage Flaherty starts come with a higher risk of downside based on his performance later in games.

If the Cardinals are going to win this game it’ll be on the back of their offensive ability, which has only been surpassed by the Dodgers in the aggregate this season.

With that in mind, favoring Flaherty in hopes of an exceptional outing over the floor that Mikolas provides is a gutsy move that could pay off big in a game where the Cardinals may very well be the underdog.

Let’s hope the Cardinals are in a spot where they’re comfortable enough to tinker with their rotation and push one of their two better starters into the wild card game. In the event this isn’t possible, at least they’ll have their two strongest starters lined up for the last two games of the season—optimism!