We all know it.

Chris Tillman can’t start another game for the Orioles right now, not with the way he has continued to struggle.

On Thursday against the Kansas City Royals, Tillman allowed a single, two walks and then a grand slam to Salvador Perez before recording an out. He escaped further damage in the first, and the Orioles scored three runs in the bottom of the inning to dig out of the four-run hole.

And then Tillman surrendered two more runs (one earned) in the second inning on a seeing-eye single before he was mercifully pulled by manager Buck Showalter.

“Same challenges he’s had. Stuff was a little short and command was short. That’s a bad combination,” Showalter said. “It’s tough to watch him struggle like that, especially with the success he’s had in the past.”

That’s five runs allowed in 1 1/3 innings Thursday on the heels of his one-inning, seven-run stint in Anaheim last week. So Tillman, whose ERA is 10.46 in seven starts this year, has allowed 12 runs in 2 1/3 innings in his last two starts, after giving up just one hit in seven scoreless innings April 27 versus Detroit.

“It’s frustrating any time it happens. One in a row, two in a row, it really doesn’t matter,” Tillman said. “It’s always frustration. As starters we know we’ve got to get deeper in the game and give the team a better chance to win than that.”

Including his disastrous season in 2017, Tillman has pitched to an 8.42 ERA in his last 31 games (26 starts) – the highest ERA of any major league pitcher over that stretch with a minimum of seven starts.

His results – somehow – are worse than last year, when his season didn’t start until May due to shoulder discomfort.

There’s not much more to say here.

This appears to be the end of the line for Tillman as an Oriole starter, maybe as an Oriole.

That shutout against Detroit was an outlier, not a sign of things to come. The Orioles – out of contention or not – can’t keep starting a guy who has completed four innings or fewer in four of his seven starts.

Showalter, who is exceptionally loyal to his veterans – at times to a fault – understands that, though he’s not going to publicly hammer Tillman, who was arguably the Orioles’ best starter in each of their three playoff seasons under Showalter.

“We’ll look at it and if there’s an adjustment we’re ready to make and how we’re comfortable how it affects everything else,” Showalter said. “Nobody knows better than Chris — and everybody involved — that that’s not good enough to get us where we need to (be). He’s had a couple decent games, but it’s just been frustrating for him and us.”

Tillman said he’s not thinking about whether he has lost his rotation or roster spot – his mindset has to be on fixing his command.

“I can’t worry about that. I’ve got to focus on what I’ve got to do to get better,” Tillman said. “That’s the bottom line. I have to. I’ve gotta stay focused on the game plan and keep working.”

I’ve been a Tillman supporter for years. I advocated for the club to re-sign him this winter, thinking 2017 was likely an aberration due to his truncated offseason the previous year. And I’ve seen this guy battle his way back every time the odds were against him.

But there comes a point when no matter how seriously a guy takes his craft, no matter how hard he works and no matter how stand-up of a person he is, results matter most. He has to get batters out. And he’s trying to do it with a fastball averaging 89 mph, a changeup that’s 83 and little feel for his breaking pitches – or, really, any of his offerings.

The problem is he’s not a reliever, either. So putting him in the bullpen makes little sense.

The easy answer is to place him on the disabled list and have him try to work his way back while pitching in the minors. But if he isn’t hurt, that’s not supposed to be an option. Sure, the Orioles have had plenty of phantom injuries in the past – Ubaldo Jimenez and the parking lot hole, and the mysterious Ryan Flaherty Flu are two that immediately come to mind – but that probably can’t work here.

Tillman said again Thursday, “I feel good,” when asked about his health.

So, then what?

His contract has roughly $2.3 million guaranteed remaining on that deal. Not chump change, but not prohibitive for the Orioles to eat if they decide this is it for Tillman.

They could always designate him for assignment, put him on waivers and, when he clears, then ask him to go the minors. But, given his service time, Tillman can refuse that request and become a free agent. And the Orioles would be on the hook for the remaining salary if he signs elsewhere – with the exception of a prorated portion of the league’s minimum $545,000 salary.

I can’t imagine another club would claim Tillman on waivers and pick up that contract (that includes incentives, too). But I’m sure another club would take a flyer – albeit one with a minor-league provision – banking that they can fix what the Orioles couldn’t.

The bottom line here is there are few options; none good.

It’s one of those tough times in this game when it’s probably best for both sides to amicably part ways, no matter how great the marriage once was.

Who’s up for Saturday afternoon?

The best sense was that right-hander Miguel Castro will get his first start of the 2018 season in the first game of Saturday’s doubleheader against the Tampa Bay Rays.

But due to Tillman’s short outing, Castro was needed to come into Thursday’s game in the second inning.

He pitched well, throwing 4 2/3 scoreless innings for the win. He allowed four hits and two walks, committed a balk and threw a wild pitch while striking out a batter. He threw 65 pitches, however, so that takes him out of contention for Saturday’s start.

Showalter confirmed that after Thursday’s outing.

Another possibility for Saturday, 24-year-old right-hander David Hess, allowed just one hit and struck out 10 batters for Triple-A Norfolk on Tuesday morning. He’s on the 40-man roster, and has already been called to the majors once (but didn’t pitch) this year.

Because he threw 84 pitches Tuesday, however, the Orioles aren’t likely to have him make his first big league start on short rest, though they could call him up to be in the bullpen.

It was short-sighted to have him start Tuesday, but what is done is done.

Otherwise, options are limited on the 40-man roster. Jimmy Yacabonis would be on regular turn, but he hasn’t pitched deep while starting in Norfolk. It’s possible he and Hess could be called up together and could tag team the start – the Orioles are allowed a 26th man for the doubleheader.

Or Mike Wright could get his third start of the season, but he allowed five runs in 4 2/3 innings on Tuesday. Top prospect Hunter Harvey threw five innings Wednesday at Double-A Bowie, so count him out, too.

All we know for sure is Alex Cobb will pitch the nightcap.

And the possibilities for Saturday are far from ideal.