Philadelphia, PA (Sports Network) - Is it me, or has something been missing from the world of professional tennis for the last seven months?

Oh, yeah ... Rafael Nadal.

The Spanish strongman hasn't lined up since the last week of June last season after succumbing to a knee injury, as well as little-known big-serving Czech Lukas Rosol in the second round at The Championships, Wimbledon. It's probably safe to say Rafa suffered one of the biggest upsets in tennis history that day because of the bad knee.

But who knew at that time the former world No. 1 seven-time French Open champion and 11-time Grand Slam titlist would embark on the lengthiest layoff of his brilliant/injury-slowed career.

The 26-year-old Nadal will make his long-awaited return this week when he plays on his beloved clay at the ATP event in Chile, specifically in the resort town of Vina del Mar, or "The Garden City."

A poker-faced Nadal has already asked everyone who will listen to lower their expectations for him ... especially this week.

"I need weeks of working on the circuit," he cautioned. "This is my first week and I don't think the goals are the same that the ones I will have in two more months. I have to take it slowly and be humble to know that things won't be as good as they were before my injury. I need to be patient.

"I hope the tournament will help me to get the feeling I need to add week after week after a long period without competition. Results are the least important thing right now."

Retired American star Andy Roddick doesn't agree with Rafa's assessment, tweeting this week: "I'll save the suspense as far as nadals return this week. If he plays the tournament on clay this week, he rolls to the title ...."

Nadal could potentially meet his doubles partner, Juan Monaco, in the final. The second-seeded world No. 12 Monaco happens to be the reigning champ in Vina del Mar, having beaten fellow Argentine Carlos Berlocq in last year's finale.

Since Nadal landed on the sidelines last summer, he has fallen to No. 5 in the world. And he ended last season outside the top two for the first time since 2004. That amazing stretch means Rafa finished 1 or 2 in the world seven straight years. Wow!

Last year, Nadal captured an Open Era-record seventh French Open title, including a third straight. The deluxe dirtballer nailed down four straight championships at Roland Garros from 2005-2008.

The career Golden Slam holder (all four majors and Olympic gold) was forced to miss the Olympic Games in London, the U.S. Open and the prestigious season- ending ATP World Tour Finals, also in London, last year, which wound up being an almost forgettable one for the Mallorcan superstar. Rafa also missed the first major of this year -- last month's Australian Open -- as well as last year's Davis Cup final (Spain lost to the Czech Republic, 3-2) and this year's Davis Cup opener (Spain lost Canada, 3-2) ... so he has some catchin' up to do.

Trivia: Who is the only other male player to capture a career Golden Slam?

Nadal was also a runner-up at the Aussie Open last year, which means he reached finals at two of the three Grand Slam events he played in 2012. And before he lost at Wimbledon, Rafa had appeared in five straight major finals, which included a pair of Roland Garros titles.

Not bad.

The powerful Nadal is the top seed in Vina del Mar and enjoyed a bye into the second round, where he'll face Argentine Guido Pella (who?) or a qualifier.

Vina del Mar kicks off the "Golden Swing" portion of the ATP calendar in Latin America and Nadal will appear in a South American event for the first time since 2005, when he won a title in Brazil as a spry 18-year-old.

Nadal was greeted by Chilean president Sebastian Pinera upon his arrival last week.

The "King of Clay" owns 50 career titles on the ATP circuit, including a whopping 36 on the dirt.

Is the gritty southpaw the greatest clay-court player of all-time? It sure looks that way. Sorry, Bjorn (my tennis hero) Borg.

Trivia Answer: American icon Andre Agassi is the only other men's career Golden Slam ace.

Even following his epic layoff, if Nadal can stay on the court for the next few months, he'll be the favorite at the French Open once again. It's hard to argue against that considering he's an amazing 52-1 at Roland Garros, where his only (shocking) loss came at the hands of Robin Soderling in the fourth round there four years ago. And Nadal was slowed mightily by a pair of sore knee that day.

So it's time to get back to the business of the "Big Four," who probably represent the greatest top-four group in the history of tennis, with Novak Djokovic, Roger Federer, Andy Murray and Nadal banging heads for tour supremacy. The 17-time Grand Slam king Federer has had the best career of anyone to this point, but Rafa is no slouch, and Djokovic bas been piling up the major titles over the last few seasons to get his name in the all-time- greats mix.

Did You Know?: Nadal and Federer have never met at the U.S. Open.

I don't know about you ... but I expect Rafa to return with a title this week.

The Sports Network