Sock undergoes surgery, will not play Australian Open

Fourth-ranked American Jack Sock has undergone surgery and will not be able to play until February, he said in a tweet:

The 22-year-old finished 2014 at a career-high No. 42 ranking and won the Wimbledon doubles title with Vasek Pospisil; the Canadian-American duo stunned the Bryan brothers in a five-set final.

In singles, Sock reached his first ATP semifinals, upsetting John Isner in the Newport quarterfinals before falling to Lleyton Hewitt, then losing to Isner in the final four of Atlanta. Sock nearly defeated Milos Raonic in Toronto but lost in a third-set tiebreaker. He was forced to retire at the U.S. Open in the first round of singles due to an injury.

Sock played fairly well in his return, reaching the quarterfinals of Tokyo and defeating now-No. 5 Kei Nishikori in the second round of the Shanghai Masters. He then qualified for the Paris Masters, were he upended Pablo Andujar in the first round before losing to Raonic. He finished the year 27-20 in singles competition.

Sock is the youngest American in the Top 100, with Isner, Sam Querrey, and Steve Johnson ranked above him, and Donald Young ranked just below him.