But ever since moving back to full fitness, the 38-year-old midfielder has been one of the best players in Major League Soccer.
The former Chelsea and West Ham United man admitted his long injury break, which came with plenty of criticism that he was one of the worst signings in league history because of his inactivity, was frustrating to sit through because he wanted to please the fans of the second-year club.
“It was frustrating," Lampard told Bleacher Report. "I’m not the only player to get frustrated when being injured. It was tough and it was a difficult injury that probably wasn’t as well-documented out loud than what it was behind the scenes and I knew I was going to be out for a while.
"It didn’t come across, so it was probably frustrating that I couldn’t get out and do my thing on the pitch to show people what I could do. I just tried to keep a calm head so when I did get fully fit, I could help the team. I wouldn’t call it a relief to be back, it was just something I really wanted to show what I came here for."
Lampard's form in front of the net isn't the only thing he's attributed to NYCFC's spot atop the Eastern Conference standings entering Saturday's home clash with the LA Galaxy.
"I think more than anything it’s a combination of hard work from preseason," Lampard said. "We obviously had a tough first year. From the first day of Patrick (Vieira) and his staff coming in, they’ve worked really hard with the squad every day.
"Results don’t come overnight and in the last couple months there’s been a bit of click in the way we play and as a team the way we’re moving the ball and we’re playing some really good football, scoring goals, winning games and getting the consistency is a combination of what we’ve been putting through since January."
Lampard's relationship with first-year manager Patrick Vieira has been important to his success at the club. Vieira took over in the offseason for Jason Kreis, who led City to an eighth-place finish with 37 points. NYCFC already have eclipsed that total as they lead the East with 38 points, one point ahead of the star-studded Toronto FC.
"To me, he’s been a revelation to the club," Lampard said of Vieira. "We had a tough year last year for so many reasons and unfortunately the manager changed, but with Patrick coming in and what he’s brought to us in terms of his personality and experience, I know he’s an inexperienced manager, but his experience with being a player has set himself up for that."
Vieira was supportive throughout the difficult process Lampard went through in recovering from his injury. Due to the positive manner in which the manager approached the situation, Lampard feels that his strong play on the pitch is repaying Vieira for his faith early in the season.
"I’ve found Patrick to be a brilliant person with me," Lampard said. "He’s always been speaking with me, keeping me calm when I was frustrated. I’m very thankful for Patrick, and I want to thank him for my recent form. I want to thank him back by producing on the pitch."
Not only is Lampard impressed with his new manager, he's thrilled that the play in MLS has lived up to his expectations.
"I think I had a good understanding of MLS before I came here," Lampard said. "I knew it was a tough league to play in, and it hasn’t disappointed. Teams are very well prepared. There’s a lot of good attacking teams out there. They’re always trying to play positive football so the hard things that have come along are things I completely expected, and the league has been nothing but impressive to me."
One of Lampard's first matches back was the New York derby with rival New York Red Bulls. The rivalry is becoming one of the fiercest in MLS and eventually it may take over the Seattle Sounders-Portland Timbers clash as the best in the league.
Despite NYCFC's rough record in the derby, Lampard believes the competitive culture between the two sides is only growing the stature of the sport in one of the biggest cities in the world.
“I think it’s a healthy rivalry," Lampard said. "We all enjoy rivalries in sport and I think our premise was when we were formed to be the club of the city within the five boroughs and we are that. Of course you have the Red Bulls that are very close. Maybe they’re fighting for fan base. That’s normal. We’re used to that."
"Then it comes down to the club and how you work on and off the pitch in the community," Lampard said. "Even more than that, you have to get results on the field because winning games is always going to grow your fan base. That’s our challenge.
"Red Bulls have been around a while and haven’t been able to win MLS Cup, and we want to within our short-term history really challenge for that. It’ll be really interesting to see how the rivalry develops over the next few years."
Lampard arrived in MLS following a stellar Premier League career with West Ham, Chelsea and Manchester City.
During his 13-year stint at Chelsea, which was sandwiched between spells at West Ham and Manchester City, Lampard played alongside plenty of world-class talents. He identified players like Eden Hazard, William Gallas and Ashley Cole as the best he played alongside in west London
Lampard also mentioned the high-quality stars who he took the pitch with at Manchester City, NYCFC and on the international stage with England, including the likes of Wayne Rooney and Rio Ferdinand.
As for his current superstar teammates, Pirlo and David Villa, Lampard has enjoyed playing with them, but although the three former European stars are in the spotlight constantly, the rest of the squad has put in a massive amount of work as well to make 2016 a successful season.
"It’s great playing with (Pirlo and Villa)," Lampard said. "They’re obviously world-class players and have had fantastic careers and that speaks for itself. I think with David as a striker, it’s great playing with someone who scores goals out of nothing because they win you games. He’s always making the right runs, in the right areas and can finish."
"Pirlo’s very easy to play with because his awareness on the ball is so good. I think we have a nice link on those terms and we understand each other. What we’re doing and how everybody’s performing as a group has been really impressive to me, not just us three but everybody."
Given the recent form of the player and the club, 2016 could go down as an historic season for NYCFC, and it could give Lampard a chance to leave a legacy in a short time at a club that carries an incredibly high standard for success.
Joe Tansey covers MLS for Bleacher Report. You can follow him on Twitter, @JTansey90.
All quotes obtained firsthand unless otherwise noted.