LOS ANGELES -- Jack Flaherty experienced a noticeable dip in fastball velocity during his last start, averaging 91.4 mph in Game 5 of the National League Championship Series and triggering concerns about the state of his arm as the season stretched into late October. Flaherty, who will start Game 1 of the World Series for the Los Angeles Dodgers on Friday night, said the drop stemmed from a timing issue with his delivery that he has been working to correct throughout the week.

Dodgers pitching coach Mark Prior said the issue is not injury-related, though he acknowledged to being "moderately concerned."

"Moderately concerned," Prior said. "Obviously everybody knows -- the more velocity the better, usually. As long as you're going way below hitting speed. Concern, yeah, because obviously he was pitching on regular rest and it was a little bit down. Can he pitch with it? Yeah. He's somebody who's more about execution that anything. And I think they did a really good job of game-planning the second time through, sitting on some of their slower spin stuff. But I think with extra rest and what we saw in bullpens, I feel pretty confident that he can get back to where he was the other time."

Flaherty pitched seven scoreless innings against the New York Mets in Game 1, then allowed eight runs in three innings against them from Citi Field in Game 5. The latter start saw Flaherty's four-seam fastball fall by nearly two ticks, from a season average of 93.3 mph. His average fastball has now dipped below 92 mph in three of his last five starts. The mechanics of his delivery tend to impact that.

"And sometimes it's intent," Prior said. "He's a little bit old school where sometimes he'll throttle his heater so that he can jump on it a little bit late. We've seen that since the beginning. I know his velocity over the year is up a little bit more, but we've seen him pitch at 91 very effectively, and then next thing you know he's 94, 95. He has the ability to go get it when he needs to. Sometimes when his delivery is a little bit off, though, it makes it a little bit more challenging to go get it."

At this time of year, the amount of days off between starts might also have an impact. Flaherty was on six days' rest when he dominated at the start of the NLCS but was on the traditional four days' rest when he struggled in Game 5. When he faces the New York Yankees in Game 1, he will once again be on extended rest. But he'll be on four days' rest once again when he makes his second start, from Yankee Stadium in a potential Game 5.

Asked if that's a concern, Roberts said: "I think that, No. 1, we don't have a different alternative. And, No. 2, we're going to dig into that as far as the stuff kind of seems like it's been down on regular [rest]. But that's kind of the way we set up the rotation, and that's just the way it's going to be."