The world No. 2 played just nine events this year, finishing just seven. (AP)

Rafael Nadal played a unique season in 2018, to say the least. The Spaniard competed in just nine events, and yet still nearly ended the year at No. 1.

What hurt him most, obviously, was missing the entire fall season, as he dealt with knee, abdominal and ankle injuries. Novak Djokovic ultimately passed him in the rankings in Paris, and then secured the year-end No. 1 spot when Nadal withdrew from London. 

The 31-year-old was spotted on crutches after undergoing an ankle operation to remove a loose bone fragment on Monday. 

Many drag Nadal for not doing more to preserve his body, but nine events in a season is some serious self-preservation. Not only did he put an emphasis on clay (five of his events were on dirt), but he also severely limited his hard-court play. By year's end, Nadal had completed just one hard-court event (Toronto, which he won). Overall, he won more than half of the tournaments he entered (five) including his 17th Grand Slam title in Paris. 

He retired or withdrew from 11 outdoor and indoor hard-court tournaments. His retirements included the Australian Open quarterfinals and US Open semifinals, while his lengthy withdrawal list includes Brisbane, Acapulco, Indian Wells, Miami, Cincinnati, Beijing, Shanghai, Paris and the ATP Finals in London.

Compare that with last season when he played 18 tournaments, and completed every single one except for his last event, London. Nadal has yet to win a year-end championship in his career.

With the surgery behind him, hopefully Nadal can regain full health in time for the 2019 season. He postponed an exhibition in Mallorca (to help victims from the recent deadly flood) scheduled for Dec. 7, but he's still scheduled to play an exhibition against Novak Djokovic in Saudi Arabia on Dec. 22. 

This Week on Tennis Channel:

Fed Cup Final (Sat. 11/10 to Sun. 11/11)
Petra Kvitova leads the Czech Republic against defending champions USA. Live coverage begins Saturday at 8:00 am EST.