Serena Williams to Drop Out of Top 10; Venus Out of Top 5

The year hasn't started off well for the Williams sisters, and there doesn't seem to be much light at the end of the tunnel for the injured pair.

The dominant sisters, who have won 12 Grand Slam doubles titles together, are both projected to have their WTA rankings plummet following the Australian Open.

The younger Williams, Serena, was ranked No. 1 on tour last season before injuring herself in an off-court incident that required surgery shortly after Wimbledon. The 13-time Grand Slam singles champion, who won last year's Australian Open and Wimbledon singles titles, has not returned to the tour following the accident last July.

Unable to defend her title at Melbourne Park, Serena is projected to fall out of the top 10 and is estimated to hover around the No. 13 spot, the WTA told The Associated Press. It will be a three-year low for Serena, who was ranked No. 4 entering this year's Australian Open.

The outlook doesn't look positive either, as Serena has reportedly noted she will most likely not return to the court until the spring.

Additionally, she has been under the weather and tweeted this on Sunday: "My throat feels raw. every time I take a sip of sumthin [sic] it feels like i just swallowed 20,000 mini knives. its 5:10am"

The older Williams, Venus, valiantly overcame an injured hip muscle during her second-round match at the Australian Open last week. But the injury was too much for the fifth-ranked player to endure and she retired just minutes into her third-round match against Andrea Petkovic.

It was the first time in her career -- spanning 251 matches -- that she had to retire during a Grand Slam match. Venus, who has won seven Grand Slam singles titles, is projected to fall out of the top five when the new rankings are released.