The team that entered Citizens Bank Park this weekend on a 93-win pace was without its third baseman, leftfielder, catcher, and fourth starter. The Phillies, for once, could boast health while Washington adjusted without key pieces like Bryce Harper and Ryan Zimmerman.

A middling first half is what doomed the Nationals a season ago, and there were lessons learned by a team widely predicted to win the World Series, not watch the entire postseason from home.

"You have to start with depth," Jayson Werth said, "and you need depth right behind that."

On Friday night, before the series' first game, Werth greeted his former Phillies teammates behind the batting cage. He saw all of them healthy for the first time in years. There was no need - yet - for the Phillies to test that important depth. That is what makes May a most crucial time.

For two years, team officials lamented the roster's poor health. Still, this winter, general manager Ruben Amaro Jr. built around the edges of his veteran core by adding 36-year-old Marlon Byrd and 37-year-old A.J. Burnett. He bet on the older players' ability to stay on the field. That investment formed a .500 record in April, most of which was played without $144 million ace Cole Hamels. A similar record in May with a full roster at Ryne Sandberg's disposal could be an indictment of that talent.

"That is a veteran club that knows how to win," first-year Washington manager Matt Williams said of the Phillies. But if the veterans cannot escape mediocrity while healthy, what is to come later when one, two, or even three regulars succumb to injury?

The Phillies embarked last week on a 30-game stretch in which 22 will be played at Citizens Bank Park. Until now, with the exception of a five-day stretch in July 2012, the Phillies have played the last two seasons with a member of their everyday lineup or starting rotation on the disabled list. The timing is ripe for wins.

Scouts remain skeptical about the Phillies' chances. Fans, too, require convincing. The Phillies entered the weekend 13th in average attendance, which was hurt by poor April weather and a single weekend at home before this series. They registered an average decrease of 9,129 fans over the first 10 home games when compared to the first 10 last season. That was the worst decline in baseball.

The numbers, when compared to 2012, are staggering. The Phillies drew an average of 45,410 fans over their first 10 home games in 2012. It dropped to an average of 28,987 fans this season. That means the Phillies sold 164,223 fewer tickets in the first 10 games of 2014 than they did two seasons ago.

That is meaningful to the team's bottom line. The trend, of course, can alter with consistent winning.

A lack of depth is what doomed the Phillies in the last two seasons; Washington endured its shortcomings in 2013. The Nationals finished the season at a 34-20 clip. That was not enough to atone for a 48-47 first half. That is why a quality start in 2014 with a depleted roster provided hope for Werth.

"When you lose some veteran, character guys, it has an effect," Werth said. "This year we did a good job. We got Nate [McLouth]. We got [Kevin] Frandsen. That makes a difference. But they also have to produce."

The Nationals will play all of May without Zimmerman and Harper. Zimmerman could return in early June from a broken right thumb. Harper will not be ready until July after recent surgery on his left thumb. Doug Fister, a marquee addition in the winter, will not make his Washington debut until Wednesday because right elbow inflammation slowed him. Wilson Ramos, the talented but oft-injured catcher, is not too far behind Fister in his recovery from left hand surgery.

Washington plugged Danny Espinosa, 27, at second base and moved 23-year-old Anthony Rendon to third. Both produced at a high level in April. The combination of veterans McLouth and Frandsen have replaced Harper in left. Tanner Roark, an unheralded 27-year-old righthander, allowed 10 runs in his first five starts this season as Fister's sub.

"You need that next level, that prospect, those guys champing at the bit to get up here," Werth said. "That's just as important as having a strong bench. Guys are going to get injured. The guys who fill in for them better be able to play better than average."

The Phillies, after May, should know whether they are better than average.