For Rafael Nadal, it's not a question of talent or ability on the grass—his five career Wimbledon finals appearances and two titles are evidence of that—but of rust.
Not overall rust. In nine tournaments since returning from a seven-month injury hiatus, Rafa has made a staggering eight finals in a row, including wins in Barcelona, Madrid and Rome before emerging victorious at Roland Garros for a record eighth time.
After such a dominant run, it's apparent that he's back to form.
Instead, the only thing potentially holding Nadal back at the All-England Club will be rust on the grass.
It's been two years since he has had success on the semi-fast surface.
After advancing to the 2011 Wimbledon final before eventually bowing out against Novak Djokovic, Nadal was looking for redemption in 2012.
But he came nowhere close to that.
He lost to Philipp Kohlschreiber in the quarterfinals at the Gerry Weber Open before finding himself on the wrong end of the most shocking upset of the year when he lost to then-world No. 100 Lukas Rosol in the second round at Wimbledon.
That was his final match before his extended absence.
Fast-forward to present day and Nadal is getting prepared for Wimbledon with no grass warm-ups under his belt:
All things considered, we're going to know very early on whether we're getting the Nadal that has won an unbelievable 85.71 percent of his matches at the All-England Club or the Nadal that hasn't played a healthy match on grass for over 700 days.
As such, his first few matches—albeit against lesser opponents—will be vital in his overall tournament success. How he trains, how he adjusts to different adversaries and different styles and how his knee reacts to the grass will all be extremely important.
Nadal admitted to Sky Sports how important it will be to hastily get back into the flow of things:
"I am going without having trained on grass and it is a surface that you have to understand, learn once again and know how to play the points and focus in the right manner in certain situations," said the world No 5.
"I have gone practically two years without playing on grass because last year I arrived in very bad condition due to the knee, just as much in Halle as at Wimbledon.
"So I have to work from today, doing things right and trying my hardest in every training session, which is the only way to arrive at the first round in good condition."
Moreover, the opening rounds are when the grass is fastest and Nadal is most susceptible.
It will be more difficult for him to display his world-class defensive abilities, not to mention we still don't know how his knee will fare on a surface faster than clay. But as the days pass and more tennis is played, the grass will slow and Nadal will be the benefactor.
This is shaping up to be one of the most unpredictable Wimbledon tournaments in recent memory.
If Nadal's condition turns out to be a concern in the opening rounds, you could see another early exit.
If he passes the eye test and gets past the first week, however, his sixth championship appearance is all but inevitable.