One of the worst things that can be said about a professional athlete is that he’s mentally soft, that he caves in under pressure. If it is said, it’s usually said in hushed tones.

Just two months into Yu Darvish’s career as a Cub, it’s being talked about matter-of-factly.

The idea that the team’s big offseason signing lacks mental toughness is widespread in Chicago now. In almost every conversation I’ve had with fans or media members, it has come up. In a column about the Cubs’ first 30 games this season, I wrote that “there is already open talk about his ‘soft’ mental makeup.’’ No one contacted me to disagree.

Is the perception of Darvish fair? How do we know that the Cubs right-hander buckles at the first hint of trouble? How would we even measure that?

I don’t have the answers to any of those questions. It doesn’t reflect well on anyone that he’s being judged so harshly after only six starts in a Cubs uniform. But that’s almost beside the point now. Once the perception of mental weakness is out there, especially in as macho a sport as baseball, it’s extremely difficult to make it go away.

Darvish has a massive salvage operation in front of him. He has to rescue his reputation. The only way for him to do that is to win. Not just now but in October.

Until last year’s World Series, he had a reputation for being a hugely talented, hugely sensitive pitcher. Looking back on it, those were the good, old days. “Hugely sensitive’’ has given way to “incredibly soft.’’

How did we get from there to here?

Darvish pitched poorly in the World Series last season, losing two starts while lasting a total of 3 1/3 innings for the Dodgers. He is 0-3 with a 6.00 earned-run average this season. His Waterloo so far has been the fifth inning, in which he has a cartoonish 31.50 ERA. That has led to the soft label. One minute, he’s cruising; the next, he’s walking someone in the fifth and falling apart.

Cubs fans booed him at Wrigley Field in his most recent start, a May 2 loss in which he gave up five earned runs and three homers. He was pulled in, yes, the fifth inning. Five days later, the team put him on the 10-day disabled list with the flu. He was eligible to pitch Monday in a makeup game at Wrigley against the Braves, but the Cubs chose to wait a day and start him Tuesday in Atlanta. Manager Joe Maddon denied that the team was holding him so the embattled pitcher wouldn’t have to face Cubs fans in his return from the DL.

The Cubs signed Darvish to a six-year, $126 million contract in the offseason, all but choosing him over Jake Arrieta, who had helped them win a World Series in 2016. Oh, and Arrieta has been great for the Phillies.

In other words, everything that could have gone wrong for the four-time All-Star has.

On Sunday, a reporter asked Maddon if he was worried about his pitcher’s mental state.

“I’m not,’’ he said. “I mean, honestly, I’m not. The guy’s been really good for so many years. He’s got an outstanding arm. I think sometimes he gets a little bit speeded up in what he’s doing. He and I have talked about that. But there’s too much success there for me to be worried about that. He would not be in the position he is if that were in fact true.’’

We’re always looking for deeper meaning. Why wasn’t Maddon offended by that question? Why didn’t he defend Darvish more vociferously? By even answering the question, was there tacit agreement that the topic of mental toughness is a legitimate one? Maybe we’re analyzing things too much these days.

(It’s interesting that a sport beholden to analytics, a sport overrun by number crunchers, would turn so quickly to a player’s mental makeup, something that can’t be quantified, when looking to explain his struggles.)

Darvish hasn’t been here long, yet he’s already elbowing his way into the rogue’s gallery of unpopular Cubs, a group that includes Todd Hundley, Corey Patterson and Milton Bradley.

That says as much about us as it does about him. It speaks to the immediacy of our times, to the need for instant gratification. It very well could speak to his emotional shortcomings. But perhaps we should give this a little more time before we chalk it up to a weak mental constitution.

We have to leave open the possibility that Darvish will find himself again. If he does, whom does he contact about getting his reputation back?

Legendary Sun-Times sports columnists Rick Morrissey and Rick Telander are co-hosts of a new podcast called “The Two Ricks: Unfiltered.” Don’t miss their gritty, no-holds-barred takes on everything from professional teams tanking to overzealous sports parents and more. Download and subscribe for free on Apple Podcasts and Google Play, or via RSS feed.