"I don't know," Herndon said. "It's just the one pitch I've had a ton of success with. I just keep going to it."
Early in the season, Phillies manager Charlie Manuel has used Herndon in low-leverage situations. So far, Herndon hasn't disappointed. That could mean more important opportunities down the line.
The question is: As the scouting reports circle the National League about Herndon's heavy reliance on his sinker, will he have to use his breaking ball more?
"We'll see," pitching coach Rich Dubee said. "I mean, he's got a great sinker. But there will be times he will have to protect it."
Herndon injured his right shoulder during his freshman season at Gulf Coast Community College in Florida. When he came back for his sophomore season, he dropped his arm slot to about three-quarters because it still hurt to throw from over the top.
That's when he noticed his fastball started to move. And it was the birth of a sinker, the pitch that allowed Herndon to skip triple-A completely and make the Phillies.
But he continues to work on his slider as a secondary pitch. Friday night, Herndon used five sliders out of 36 total pitches. Only one of those sliders was a strike.
Herndon said there were times last season in double-A when he threw more sliders than sinkers in a game. When he faced a team that had seen him often, Herndon switched it up.
"The guys were backward," Herndon said. "They were clueless."
But that was the minors. Herndon said he will reach a point sometime soon when he will have to tweak what he does, just to keep hitters guessing.
The sinker isn't going anywhere, though.
"Regardless if my breaking stuff is great, I'm still going to be primarily a sinker guy," Herndon said. "It's what got me here. And hopefully, that's what is going to keep me here."
Closer Brad Lidge (elbow, knee) pitched in his first rehab game for single-A Clearwater on Saturday and couldn't finish an inning. He allowed four earned runs on three hits and a walk in two-thirds of an inning.
Lidge was pitching in a game situation for the first time since he received a cortisone shot March 30 to help boost his velocity. The Phillies had been pleased with his recent progress.
Also, lefthander J.C. Romero pitched a scoreless inning for Clearwater in his second rehab outing. He allowed one hit and struck out two.
First-base coach Davey Lopes will rejoin the team Monday for the home opener. Lopes left the Phils on April 2 after learning of his brother's death that day in a house fire in Providence, R.I. . . . According to the Elias Sports Bureau, third baseman Placido Polanco is the first Phillie with more than 10 hits in his first four games of the season since Johnny Moore in 1935. . . . Roy Halladay makes his second start of the season Sunday opposite Houston's Roy Oswalt. Halladay is one victory shy of 150 in his career.
Contact staff writer Matt Gelb at 215-854-2928 or firstname.lastname@example.org.