PURCHASE, N.Y. – It is a marquee MLS matchup, the leaders of the Eastern Conference against the second place side in the West.

New York City FC and the Colorado Rapids have been two of the biggest success stories during the first half of the 2016 campaign and, on Saturday at Yankee Stadium (3 pm ET, MLS LIVE), the squads meet for the only time during the regular season.

But Patrick Vieira’s side enters the showdown without several key starters, including captain David Villa, the league’s leading scorer who is suspended because of yellow card accumulation.

The same is true of fullback RJ Allen and midfielder Federico Bravo, while fullback Ethan White sits after a late sending off against the New York Red Bulls last Sunday. Costa Rican international Ronald Matarrita is still working his way back from an ankle injury, recent signing Maxime Chanot just arrived from Luxembourg Thursday, and then there’s the question of Andrea Pirlo’s availability.

The Italian midfielder was in Dominic Kinnear’s starting XI for the MLS All-Star Game against Arsenal at Avaya Stadium on Thursday, and, along with Villa, played the first 32 minutes before being subbed off.

The 37-year-old left the field and shortly thereafter left the stadium to catch a flight back to New York.

“I’m going to speak to Andrea and I’m going to see how he feels. If he’s OK, if he’s good, of course I will play him,” Vieira said. “If he says to me he is tired because of the flight, of course I will not take any risk because flying 3,000 miles to go and play a charity game and then fly back 3,000 miles will be risky for me to play him. I will speak with him before making a decision.”

Vieira has a lot of decisions to make, though he said he is committed to maintaining his 4-3-3 formation.

Jason Hernandez has already played on the right of NYCFC’s back four and is likely to be featured there again against the Rapids, while Diego Martinez might be Vieira’s only option at left back and is likely in line for his second start of the season.

If Pirlo isn’t available, Mikey Lopez, Mehdi Ballouchy and Mix Diskerud are Vieira’s options, while Tony Taylor, Steven Mendoza or Khiry Shelton will start in place of Villa.

“Of course it’s a big blow for us, but that will give opportunity to the other players to show that they deserve to play,” Vieira said. “This is a message I’ve been sending since the beginning of the season.”

Finding goals against Colorado would be difficult even for a full-strength NYCFC. The Rapids, second in the West with 38 points and holding three games in hand on first-place FC Dallas, lead MLS with just 14 goals conceded in 20 matches. And they come to Yankee Stadium riding a 15-match unbeaten streak.

“I don’t think they score a vast amount of goals and they’re not killing teams, but they’re secure as a group,” said midfielder Frank Lampard of the Rapids. “I think they defend very well. I like the players they’ve got in behind the front men. They play good football in and around the box.”

Lampard spoke glowingly of forward Kevin Doyle and goalkeeper Tim Howard, two former English Premier League opponents. And Vieira is a fan of Rapids coach Pablo Mastroeni, whose MLS Cup-contending team has taken on his personality, he said.

“I really like their manager. I like his character, he’s really lively, he looks like a proper winner,” Vieira said. “I strongly believe his team reflects the manager. It’s a really strong team to beat when you look at the record of the number of goals conceded. They look really solid, a team that is well organized and the four players up front have got quality on the ball.”