Nick Williams likes to swing, and that is why the Phillies both appreciate him and fret about him. He enjoyed a 12-game hitting streak earlier in September, a streak in which he batted .415 with seven of his 22 hits for extra bases. Then, in his next 11 games, he hit .184 with 16 strikeouts in 38 at-bats.

The 24-year-old outfielder has flashed a flair for driving in runs. That is one reason the Phillies believe he could be a middle-of-the-order bat. But his strikeout and walk rates have regressed, almost to what they were at triple A upon his promotion.

It is something to note, heading into a winter that is full of intriguing decisions to be made by the Phillies' front office.

Williams sat Tuesday against Washington's tough lefthander, Gio Gonzalez. But, with more and more looks at him, opposing teams had begun to target holes in Williams' swing. One visible weakness is the high fastball, a pitch Williams often chases.

"I think they're trying to exploit that," Phillies manager Pete Mackanin said. "He strikes out an awful lot. He's a dangerous hitter. If you make a mistake, he's going to get you. He knows what he has to do. He has to tone it down a little bit but stay aggressive. So that's something he's working on. That's not easy to do. But that's what he's trying to improve upon."

In a modern game in which strikeouts matter less than they ever have, Williams can be a productive player despite his high strikeout rate. The margin is just thinner because of his aggressiveness.

Williams, in 323 plate appearances with the Phillies, has posted a 28.8 percent strikeout rate and 5.6 percent walk rate. Those almost mirrored his minor-league rates (29.4 percent and 5.2 percent) in 306 plate appearances this season. No Phillies hitter with at least 200 plate appearances this season has a lower walk rate and only Cameron Rupp has a higher strikeout rate than Williams.

The major-league averages for strikeout and walk rates are 21.6 percent and 8.5 percent.

"It's his first year in the big leagues," Mackanin said. "He struck out quite a bit in triple A. But he's also knocked in a ton of runs for us. I'd rather have somebody overly aggressive, then you can try to pull back a little bit."

Extra bases

The Phillies entered the night with a .752 OPS at Citizens Bank Park. That is their highest mark at home since 2010, when the offense posted a .763 OPS. … Henderson Alvarez will make one more start for the Phillies, who will stay in a six-man rotation until the end. … Mark Leiter Jr. will make his last start of the season Wednesday. He'll be opposed by Tanner Roark, who has a 3.42 ERA in four starts against the Phillies this season.