Phillies' rotation might surprise this season

CLEARWATER, Fla. -- If there is any angst about the Phillies before Opening Day next Thursday, it is the rotation.

Phillies starters ranked seventh in baseball with a 3.70 ERA through Aug. 12 last season, which was the last time they held a share of first place in the National League East. They posted a 4.19 ERA the rest of the way, which ranked 17th. Their finish is one reason why the Phillies pursued free-agent left-handers Patrick Corbin and J.A. Happ over the winter. In the end, the Phillies chose not to give Corbin the years he wanted or Happ the money he wanted, because they still believe their current group can take a collective step forward in 2019.

Not only do the Phillies see metrics that indicate they can, but they also believe they should benefit from an improved defense, deeper bullpen and more potent offense.

Time will tell.

MLB.com’s Statcast crew examined each of the Phillies’ projected five starters, and found a pitch or tendency that could be the key to their success in 2019:

Aaron Nola
Nola finished third in National League Cy Young Award voting this season. He got there with help from one of baseball’s best curveballs.

Most strikeouts on curveballs, 2018

1. Zack Godley: 134
2. German Marquez: 129
3. Charlie Morton: 117
4. Aaron Nola: 108
5. Lance McCullers Jr.: 96

Most swings-and-misses on curveballs, 2018

1. Zack Godley: 229
2. Aaron Nola: 185
3. Lance McCullers Jr.: 175
4. Jose Berrios: 158
5. German Marquez: 156

Jake Arrieta
Arrieta went 9-6 with a 3.11 ERA through his first 22 starts, but 1-5 with a 6.35 ERA in his final nine. He said an undisclosed knee injury contributed to his second-half struggles. If he returns to his first-half form and continues to generate ground balls and weak contact, it should solidify the rotation.

Arrieta’s 51.9 percent ground-ball rate was 14th out of 139 pitchers (minimum 300 batted balls allowed). He ranked seventh in poorly-hit “topped” contact at 41.7 percent.

Nick Pivetta
Pivetta is everybody’s trendy pick to have a breakout season. Almost everybody would pick Bryce Harper, Nola, J.T. Realmuto and Rhys Hoskins as strong candidates to make the National League All-Star team, but it would not be a surprise to see Pivetta there, too.

Pivetta’s 27.1 strikeout rate ranked 22nd in baseball, better than Corey Kluber, Chris Archer and Noah Syndergaard. He was one of just seven qualified starters with a strikeout rate better than 25 percent and a ground-ball rate better than 45 percent.

Lots of strikeouts and lots of groundballs are a pretty good recipe for success, no?

Pivetta’s curveball is filthy, too. Its average spin rate of 2,840 rpm ranked among the top 15 among starters (min. 100 curveballs thrown). Pivetta's quality of contact metrics on his curveball were very good, too: 175 xBA, .232 xSLG and .198 xwOBA.

Zach Eflin
Eflin’s average exit velocity (86.0 mph) was 16th-lowest out of 139 pitchers (minimum 300 batted balls allowed), only a couple spots behind Nola. Eflin’s strikeout rate also continues to climb as he cut his expected stats, too.

Strikeout percentage by year:

2016: 11.4 percent
2017: 12.5 percent
2018: 22.4 percent

Expected stats by year:

2016: .285 xBA / .490 xSLG / .351 xwOBA
2017: .287 xBA /.516 xSLG / .363 xwOBA
2018: .236 xBA / .380 xSLG / .292 xwOBA

Vince Velasquez
The Phillies are trying to get Velasquez to focus more and think less during his starts. If he does that, his stuff plays. But Velasquez has a 12.79 ERA this spring, which has Phillies fans fretting. He allowed five hits, three runs, three walks and two home runs in 3 1/3 innings in Thursday’s 13-6 victory over the Blue Jays. He struck out nine. Velasquez is expected to start Tuesday in Clearwater to build up arm strength. Because the Phillies do not have a game in three of the season’s first eight days, there is a chance he could start in the bullpen. The Phillies do not need a fifth starter until April 9.

“When his curveball and his slider were down in the zone, he was getting all sorts of swings and misses,” Phillies manager Gabe Kapler said. “And when his fastball was up in the zone, he was getting carry through the zone. Those were the two areas of focus for Vince. I thought the performance overall was good.”

Most strikeouts on four-seam fastballs, 2018

1. Max Scherzer: 132
2. Justin Verlander: 131
3. Gerrit Cole: 124
4. J.A. Happ: 112
5-T. Vince Velasquez: 109
5-T. Jacob deGrom: 109

Velasquez’s 33.3 percent strikeout rate with his four-seamer ranked ninth out of 137 pitchers (minimun 150 plate appearances ending on four-seam fastballs). His 184 swings-and-misses on four-seamers was 10th, and his 28.8 percent whiff rate on four-seamers was 16th out of 168 pitchers (minimum 250 four-seamers swung at).