Imagine if, at your real job, you simply could not perform 10 percent of the available tasks. Would that cost you your job? Would that cause your employer to fire you? I mean, you can do 90 percent of the job fine, it's just that there's a bunch of highly necessary things that you simply cannot perform.Grass season makes up about 10 percent of the regular ATP calendar. It's only six ATP tournaments (without a Masters 1000) and Wimbledon. For the dozens of clay specialists on tour, this stretch is essentially a black hole. Many otherwise passable clay specialists like Laslo Djere and Paolo Lorenzi only play the low-level Challenger events that are still held on clay in random Italian towns. Lorenzi decided to get a grass tune-up in Antalya and lost in straight sets to Mirza Basic. It wasn't great.The bottom ten players on Tennis Abstract's grass-specific Elo ratings are all abjectly terrible on grass. But the fourth-worst player by Elo, Diego Schwartzman, deserves special recognition. Schwartzman has played 7 career grass court matches and lost them all. Even Lorenzi has won a grass match, a win over fellow grass neophyte Horacio Zeballos at Wimbledon 2017.It's reasonable to say that Diego Schwartzman, the 14th-ranked player in the entire world, is one of the worst grass players in recent memory. It's hard to blame him. Diego is short, as is mentioned on every single television broadcast, and he relies on outlasting opponents and counterpunching. Those are two things you cannot do on the slick courts of Wimbledon. But still, his grass record is astonishingly poor, including a 6-0, 6-3 loss to Ernesto Escobedo and a recent loss to No. 94 Lukas Lacko.Some might say that Horacio Zeballos is a worse grass player, given that he is the lowest-ranked player by Elo. But Zeballos has actual weapons to work with on grass. He's also won an ATP match on grass and once got through Wimbledon qualifying. I'm not sure Diego could get through Wimbledon qualification, even at his current level.Some might say Pablo Carreño Busta, who has not played on grass since 2016 and has lost all five of his matches, is the true worst grass player. However, his overall game has improved drastically since 2016, and he still took eventual finalist Milos Raonic to a first-set tiebreak in that tournament. I expect Carreño Busta to comfortably beat Radu Albot in his first-round match. I do not expect Diego Schwartzman to beat Mirza Basic. Carreño Busta is a -250 favorite to win. Schwartzman is -182.This is a pointless post.