Rockies Gamble on Anderson's Wicked Slider

After watching a generation of pitching prospects mostly go bust, the Colorado Rockies have started to cobble together what could be a quality rotation with ground ball-generating starters Jorge de la Rosa, Jhoulys Chacin and Tyler Chatwood in the majors and Eddie Butler and Jonathan Gray on the farm. The Rockies added another high-upside worm-burner on Tuesday, acquiring Brett Anderson and cash from the A's for one of those stalled young arms (Drew Pomeranz) and minor leaguer Chris Jensen.

Anderson, 25, devolved from Oakland's ace-in-waiting to a training table regular thanks to an elbow injury that eventually required Tommy John surgery in 2011 and a stress fracture of his right foot that wiped out most of his 2013 season. The last time the former Diamondbacks prospect tossed even 100 innings was 2010. But Anderson has been tantalizing when able to take the mound, limiting walks (2.4 per nine innings pitched) and churning out ground balls (55 percent of pitches put in play) while compiling a park-and-league adjusted ERA that's nine percent above the league average.

The lefty's slider is a major reason why he has tormented hitters when not on the rehab trail. Anderson has thrown the sweeping, low-80s pitch more than a quater of the time (26.2 percent) during his MLB career, limiting hitters to a .270 slugging percentage. That's tenth-best among starters since 2009, right behind slider aficionado Francisco Liriano.

Why is Anderson's slider so deadly? He gets hitters to pound the pitch into the grass, and he grabs lots of called strikes by freezing opponents on sliders thrown over the plate.

Take a look at Anderson's ground ball rate by pitch location with his slider (left), compared to the league average for left-handers:

Overall, lefty starters had a 46 percent ground ball rate when throwing a slider from 2009-13. Anderson induced grounders 66 percent of the time with his slider, tops among all southpaws who regularly throw the pitch by a wide margin (Jaime Garcia is a distant second, at 60 percent).

When Anderson isn't getting grounders with his slider, he's jumping ahead in the count as hitters take breaking pitches thrown over the plate. Opponents have swung at just 57 percent of the sliders that Anderson has located within the stike zone, far below the 66 percent average for left-handed starters. With hitters gluing the bat to their shoulders, Anderson has the fourth-highest called strike rate (36 percent) with his slider among lefties since '09, trailing just Chris Sale, Ted Lilly and Mike Minor.

Coors Field and breaking balls go together like peanut butter and motor oil, but research suggests that sliders aren't harmed as much by the mile-high air as curveballs. Plus, the Rockies have paired ground ball-centric starters like Anderson with quality infield defenders (Colorado converted the sixth-highest percentage of ground balls put in play among MLB clubs in 2013). If Anderson is ambulatory, he could be a major bargain at a net $6 million salary next year and stick with the Rockies through 2015 (the club holds a $12 million option). When you're desperate for premium pitching, taking a chance on an oft-injured potential ace can't hurt.

Newly-Extended Perez Must Improve Breaking Stuff to Take Next Step

The Texas Rangers have locked up yet another young left-handed starter, signing Martin Perez to a four-year, $12.5 million extension with three club options that could extend Perez's stay in the Lone Star State to 2020 and pad his pockets to the tune of $32.5 million.

A perennial top prospect, Perez erased memories of his rough big league stint in 2012 by posting a park-and-league-adjusted ERA that was 14 percent above average (114 ERA+). The 22-year-old enjoyed arguably the best rookie season ever for a Texas lefty, as only Mike Mason (114 ERA+ in 1984) matched him while throwing 120+ innings. Perez displayed sharp control (2.7 walks per nine innings) and racked up ground balls (47.9 percent of pitches put in play), both of which bode well for his future. But he also punched out just 6.1 batters per nine frames, far below the 7.2 average for starting pitchers in this strikeout-saturated era. To get more swings and misses, Perez will have to improve his pitch location with his breaking stuff.

Perez already has an out pitch in his changeup, which generated far more whiffs (39.7% of the time batters swing) than the league average (29.4%) and limited hard contact (.307 opponent slugging percentage, 90 points below the MLB average). His curveball and slider, on the other hand, induced swings and misses just 19% of the time (29.9% average for breaking pitches) and were frequently laced into the gaps (.437 slugging percentage, 92 points above the MLB average).

Why did hitters square up Perez's breaking pitches? The young lefty struggled to command his slider and curve, too often leaving breaking balls over the heart of the plate:

Perez's pitch location with his slider and curveball, 2013

Perez threw 29% of his sliders and curves to the vertical middle of the strike zone, third-highest among lefty starting pitchers in 2013. Belt-high breaking stuff tends to get clobbered, with hitters swinging through just 12.9% of sliders and curves thrown over the middle of the plate and slugging a collective .461. Perez was no exception, getting whiffs 13.8% of the time and allowing a .556 slugging percentage when tossing a belt-high breaking pitch.

The recent history of low-strikeout lefties who nonetheless posted quality ERAs during their rookie season is mixed. On the wildly positive side, Andy Pettitte pitched into his forties and cobbled together a career that may get him some Cooperstown consideration. However, the list of low-K lefties (six or fewer strikeouts per nine) with an ERA similiar to Perez (10-20 percent better than the league average) also includes the likes of Gustavo Chacin, John Lannan and John Halama. To be more like Pettitte and less like Halama, Perez needs to complement his knockout changeup with better-located breaking pitches.

Cole Putting Hitters Away with Slider, Curve in 2nd Half

Will Gerrit Cole be a starter or reliever come October? Pirates General Manager Neal Huntington isn't tipping his hand as the first overall pick in the 2011 draft nears an unknown organizational innings limit. Whatever his role, Cole looks primed to make make an impact in the playoffs. The rookie has boosted his strikeout rate during the season's second half (from 5.4 per nine innings pitched to 7.9 K/9) and trimmed his ERA from 3.89 to 3.18.

Cole fell in love with his fastball early on during his big league career, but he's pitching more like the ace he's expected to become now that he's mixing in his breaking stuff.

During the first half, Cole threw his fastball about 77% of the time -- more often than any starting pitcher not named Bartolo Colon. In the second half, he's throwing his heater about 67%. The difference is even more pronounced in two-strike counts: 66% fastballs in the first half, and slightly under 54% in the second half.

In place of those fastballs, Cole is snapping off signifcantly more short-breaking, upper 80s sliders (six percent overall in the first half, 21% in the second half). He's throwing his low-80s curveball at about the same frequency (12% in the first half, 10% in the second). Cole is using his slider and curve as chase pitches far more often in the second half, particularly with two strikes:

Location of Cole's slider and curveball in two-strike counts during the first half

Location of Cole's slider and curveball in two-strike counts during the second half

Cole threw 44% of his two-strike sliders and curves in the strike zone during the first half, well above the 39% big league average for starters in such situations. In the second half, he's throwing just 33% of his two-strike breaking balls over the plate. Cole got eight strikeouts with his slider and curve in the first half. During the second half? Thirty.

Throwing more breaking pitches out of the zone has helped Cole put hitters away in two-strike counts. Opponents hit .246 and slugged .290 against Cole when down to their last strike during the first half (starters overall allow a .172 average and .257 slugging percentage in two-strike counts). Now that he's using his slider and curve, he's limiting batters to a .151 average and a .264 slugging percentage with two strikes. Starter or reliever? Only Huntington and manager Clint Hurdle know. Either way, Cole looks postseason-ready.