Appearances: 45 starts (+4 as substitute).
Minutes: 2750 in Premier League; 489 in domestic cups; 642 in Champions League.
Statistics (per 90 minutes, Premier League): 0.20 assists; 2.76 successful take-ons (66.67% success rate); 2.2 fouls suffered.
Although chosen as Chelsea's Player of the Year — as much a result of the rest of team's lacklustre efforts as his own hard word — Willian has yet to truly convince since his arriving in a £30 million gazumping of Tottenham Hotspur back in 2013.
Chelsea seem to be somewhat unconvinced as well, as we have acquired Mohamed Salah, Juan Cuadrado, Pedro and Kenedy — all of whom are either natural right wingers or able to play in the position — in the last 3 years to "provide depth" to an already strong attacking midfield group. On the plus side, Willian has always raised his game to see off any new or existing (in the case of André Schürrle) threats to his first-choice position.
But it would be completely unfair to discount all of Willian's accomplishments throughout the season. His importance in both European and domestic competition cannot be understated, especially when for months at a time, he was essentially the only player showing up and putting in a proper shift. Even at his best, Willian is of course no Eden Hazard, but he did finish the season with 11 goals, reaching double-digits for the first time in his career and contributing with 10 assists as well, which is a decent return for somebody mostly known for his play in build-up and transition.
Willian was ever present for Chelsea, barely missing two weeks of playing time due to injury, and keeping himself healthy while giving everything he could as an attacking midfield "dynamo". His 49 appearances were tied with César Azpilicueta and Cesc Fàbregas for most on the team, his nearly 4000 minutes set a new career high as well. Willian has also been ever present for the Brazilian national team, and there's talk of him playing not only in the Copa America but the Olympic tournament as well.
Numbers alone don't tell the whole story of "Willian the Brillian'", and we haven't even talked about his free kicks, but he was the unlikely hero, and the pretty much the only player to emerge with any sort of credit from this mess.
The Good: A stellar performance in the Champions League group stage against Dynamo Kiev, including the winning goal from a most perfect free kick.
The Bad: Having run himself ragged for much of the season, Willian's late season performances were considerably below par when compared to his previous standard. Perhaps the most obvious example was our 3-2 loss to Sunderland that ended up saving manager Sam Allardyce and his Black Cats from relegation.
The Ugly: His mid-season performances overshadowed his slow start to the season, but Willian (and the rest of the team) truly didn't cover themselves in glory in our second match of the season, a 3-0 loss away to Manchester City.
Verdict: Pedro's purchase from Barcelona in last summer's transfer window was a pretty big sign that the club were at very least looking for alternatives to Willian on the right wing. But Willian's not one to easily give up his spot, and he ended up being the one constant from the (on-paper) fearsome foursome of Hazard, Oscar, Willian, and Pedro.
Willian's work rate, especially now that Ramires is gone, is unrivalled by his teammates. In fact, it often overshadows his technical skills, which are also abundant, and his set-piece deliveries (often on par with Fàbregas), and all we see are the bad decisions and the annoying habit of putting his foot on the ball and slowing down the game unnecessarily.
There are two years left on Willian's contract and his scintillating form at the beginning of the season had led to rumors of a contract extension and a healthy payrise. That has yet to happen and has thus turned into rumors of Willian possibly looking to leave. But surely it's only a matter of time before Willian gets his proper reward.