It’s doubtful the St. Louis Cardinals would have finished with the best record in the National League and reached the World Series last season without the contributions from their rookie pitchers.

Using 12 different rookies during the regular season, the Cardinals’ collection of promising young arms posted a 36-22 record with a 3.17 ERA, 8.79 K/9 and 2.99 BB/9 in 553.2 innings.

Among those rookies was a trio of homegrown right-handers: Shelby Miller, Carlos Martinez and Michael Wacha.

While Miller opened the year in the team’s big league rotation and served as one of the National League’s better rookie hurlers before the All-Star break, Martinez and Wacha arrived later in the summer to help push the Cardinals into the postseason.

However, in spite of their respective successes last season, Miller, Martinez and Wacha each have the potential to be even better in 2014.


Shelby Miller

Shelby Miller wasn’t just one of the top rookie pitchers during the first half of the season, he was one of the top pitchers in the game. Over his first 18 starts, the 23-year-old posted a 2.92 ERA and .225 opponents’ batting average with 112 strikeouts in 104.2 innings.

The Cardinals wisely offered Miller additional rest surrounding the All-Star break after he showed signs of wearing down in late June and into July. Although he had an up-and-down second half, the right-hander completed the final month of the season on a positive note by going 3-0 with a 2.76 ERA over five starts.

Miller’s season highlight came on May 10 in his home start against the Colorado Rockies, when he surrendered a leadoff single to Eric Young Jr. before retiring the next 27 hitters in order.

Since the beginning of the postseason, however, Miller essentially has been a non-factor for the Cardinals. With fellow rookie Wacha thriving in the starting rotation after a strong finish to the regular season, manager Mike Matheny relegated Miller to the bullpen for the NLDS, mostly due to his season-long struggles against the Pittsburgh Pirates.

As a pitcher who throws his four-seam fastball 70.86 percent of the time (per Brooks Baseball), Miller can be hittable when his command of the pitch isn’t sharp. The right-hander surrendered six or more hits in 13 starts last year and allowed 12 home runs—he gave up 20 total home runs during the regular the season—in those games.

Given his heavy four-seamer use, one would think that Miller also features some form of changeup so as to neutralize left-handed batters. Yet, Miller’s changeup is actually his least used and developed offering, and the right-hander threw it only 6.41 percent of the time last season (per Brooks Baseball).

Even though Miller’s curveball is only a little better than average, his lack of a consistent changeup makes it his go-to secondary offering against lefties by default—which isn’t a good thing. The right-hander threw his curveball 16.41 percent of the time against left-handed batters in 2013, and they collectively batted .302 (.378 BABIP) with a .453 slugging percentage.

Miller used his changeup sparingly against lefties last season—11.46 percent of the time, to be exact—which speaks to both his lack of confidence in the pitch and its overall ineffectiveness (.333 BA, .433 SLG, .370 BABIP). Additionally, left-handed batters posted higher line-drive (6.17 percent) and fly-ball (5.56 percent) rates versus his changeup than either of his other two offerings. And to make matters ever more complicated, the 23-year-old struggled to control the pitch for the duration of the regular season, throwing it for a strike only 20.37 percent of the time.

In order for Miller to improve his changeup, he will first need to find a comfortable and repeatable release point for the pitch. Last season it was all over the place, varying from start to start:

Because Miller employs a clean and efficient delivery, the right-hander should theoretically be able to develop a consistent arm slot for a changeup. The pitch will probably never be a dynamic offering, but it still has the potential to be at least average if his control improves.


Carlos Martinez

Carlos Martinez struggled to find a role following his big league debut on May 3, as he was used sparingly out of the bullpen and bounced between the minor and major leagues as the organization seemingly pondered how to best utilize the 22-year-old.

By the end of the regular season, though, the flame-throwing right-hander emerged as manager Mike Matheny‘s preferred option in the late innings and ultimately served as the team’s setup man throughout the postseason.

Martinez appeared in 12 games between the team’s three playoff series, registering a 3.55 ERA and .167 opponents’ batting average with three walks and 11 strikeouts in 12.2 innings.

But in spite of his success as a reliever, the Cardinals have already stated that Martinez won’t be working out of the bullpen next season. According to Jenifer Langosch of, Martinez will enter spring training next season in the mix for a spot in the starting rotation.

The decision to use Martinez as a starter shouldn’t come as a surprise. Since entering the Cardinals’ system in 2010, the right-hander has pitched in 68 minor league games and was the starter in all but one of them. During that span, he posted a 2.69 ERA with 340 strikeouts and a 2.88 strikeout-to-walk ratio in 327.2 innings.

Yet, in his only start in the major leagues last season (Aug. 8), Martinez allowed four earned runs on seven hits and three walks in 4.2 innings against the Dodgers.

Specifically, Martinez’s arm slot in that start was noticeably different than it was out of the bullpen during the final month of the regular season and into the playoffs:

In addition to working from a slightly lower vertical-release point, the right-hander also shifted toward the first-base side of the rubber, as evidenced by his higher horizontal-release point:

Martinez had flashes of brilliance during the season but never enjoyed the success that his pure stuff suggested. However, after making the adjustment to his positioning on the rubber, the right-hander finally started to dominate and miss bats with his filthy sinker-slider combination:

Regardless of whether Martinez is used as a starter or reliever next season, he stands to benefit from developing a better feel for the movement on his sinker. As we saw last year, hitters, especially right-handed hitters, will try to achieve a point of contact in front of the plate before the pitch runs too far inside and sinks out of the zone. Therefore, even though he was able to keep the ball on the ground (17.65 percent ground-ball rate) last season, opposing hitters still were able to barrel it too consistently and ultimately posted a .320 batting average (.348 BABIP).

Based on that information, Martinez has considerable room for improvement next season if he can learn to throw his sinker to the outside corner of the plate against right-handed batters. In theory, it should at least prevent them from sitting on something on the inner half like last year, which usually translates to more off-balance swings and weaker contact.


Michael Wacha

Though he was first promoted to the major leagues in late May, Michael Wacha didn’t join the Cardinals’ starting rotation until September. Pitching in the heat of a playoff race roughly one year after the Cardinals made him the No. 19 overall pick in the 2012 draft, the 22-year-old posted a 1.72 ERA, .198 opponents’ batting average and 28/10 strikeout-to-walk ratio in 31.1 innings (five starts) over the final month of the season.

However, it wasn’t until his final regular-season start that Wacha put himself on the map as one of the game’s more promising young arms.

Taking the mound against the Washington Nationals on Sept. 24, Wacha came within one out of a no-hitter before allowing an infield single to Ryan Zimmerman. As a result of his late-season success, the right-hander was named to the Cardinals’ postseason starting rotation ahead of fellow rookie and 15-game winner Shelby Miller.

Well, needless to say it was the right decision, as Wacha finished his first postseason with a 4-1 record, 2.64 ERA and 33-12 strikeout-to-walk ratio in 30.2 innings (five starts), and captured NLCS MVP honors along the way.

In order for Wacha to take a step forward next year, the right-hander must continue to trust his breaking ball as he did in the 2013 postseason.

After throwing his fastball and changeup more than 90 percent of the time during the regular season, Wacha (as well as Yadier Molina) started mixing in more curveballs during the playoffs to avoid becoming too predictable. The change in strategy ultimately paid off for the right-hander, as his whiffs-per-swing rate jumped from 14.29 percent in September to 31.58 percent in October:

But in spite of his improvement last October, Wacha generally struggled to consistently miss bats with his curveball last season, as the right-hander’s 9.09 percent whiff-per-swing rate ranked 225th among all starting pitchers (per Brooks Baseball’s PITCHf/x leaderboard).

Even though Wacha has a good feel for his curveball and sequences it well in relation to his fastball and changeup, the reality is the pitch lacks dynamic break.

Wacha’s curveball averaged -6.17 inches of vertical movement last season, which ranked 110th among all starting pitchers. For the sake of comparison, Adam Wainwright’s curveball ranked 15th with -9.40 inches of vertical movement.

Generally speaking, the right-hander’s curveball lacks a tight rotation and reaches its peak too quickly en route to the plate. As a result, opposing hitters are able to recognize the spin early and at least get a piece of the offering. Last season, Wacha’s 45.45 percent fouls-per-swing rate was the third highest among starters that threw at least 40 curveballs.

The good news is that Wacha’s breaking ball has already improved exponentially since entering the Cardinals’ system in 2012. And while it’s completely unrealistic to think the pitch will develop into a Wainwright-like hammer, the 22-year-old’s advanced command and overall confidence should help the pitch play above its grade for a long, long time.


All PITCHf/x data courtesy of Brooks Baseball

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