Eflin working on his slider with Reading

READING - Zach Eflin's slider dipped into the dirt, and the batter offered a helpless swing. It was one of the pitcher's four strikeouts on Monday night. And it came on a pitch that Eflin deemed a "work in progress."

The righthander's slider has the chance to become his best pitch. He has mixed it in this season at double-A Reading with a fastball and change-up. He throws a four-seam and two-seam fastball, which can range from 89 to 95 m.p.h. Eflin is working with pitching coach Dave Lundquist on throwing the slider with more consistency.

"I think the biggest thing is I have to learn how to put guys away and how to throw it for strikes," Eflin said. "I've been doing a better job of that this season, and I just have to keep building on it to make it a good pitch."

Eflin, 21, was the youngest player in the Eastern League at the start of the season. He had spent the last two seasons at single A. The pitcher's age has proved to be nothing more than a number. He is 5-4 this season with a 2.76 ERA in 13 starts. Eflin seems to be the top pitcher of the three the Phillies acquired in trades last offseason.

His lone blip was an eight-run, three-inning outing on May 27. The appearance was one start after he threw a career-high 102 pitches. Take away that game, and Eflin's season ERA would be 1.91, which is just three-hundredths higher than the mark Aaron Nola, now with triple-A Lehigh Valley, recorded at Reading. Eflin pitched six scoreless innings on Monday vs. the Portland Sea Dogs.

He has allowed just three earned runs in his 24 innings since that rough outing last month. Eflin has been able to keep his pitches low this season as he controls the bottom half of the strike zone. He also shows great poise when runners reach base. He had runners on second and third on Monday with one out in the first and left the inning unharmed.

"I'm just working on getting outs. That's what's going to get people to the big leagues," Eflin said. "Getting outs and throwing quality strikes, that's what I believe in. Me being a ground-ball pitcher, I throw a lot less pitches than a strikeout pitcher. If I need to put guys away, I have the ability to put guys away."

Eflin's ability to put hitters away will likely hinge on the development of his slider. He has worked on the pitch with Reading pitching coach Dave Lundquist. The coach has asked him to throw the slider the same way as he throws his fastball, which keep hitters from knowing what pitch is coming.

"That's helped a lot," Eflin said. "My balance when I'm striding and keeping my lower half in tune, those are the biggest things I've been working on with him. Being able to get on top of it and throw it down like a fastball."

Eflin's fourth and final strikeout on Monday came in the fifth inning. Again, it was the slider. The pitch cut inside to the lefthanded batter before diving into the dirt. The batter's swing was just as helpless as the previous strikeout. Eflin walked off the mound. The inning was finished. The pitcher's slider had put another batter away.