If Holding's performance against Palace is any guide, we can trust him to move the ball around securely and with confidence, go hard with good technique in his duels, play with an understanding alongside Gabriel and White, and read what's occurring in a match.
Holding's one outstanding weakness (and it's big) is his foot speed. He is going to be far slower on recovery than most forwards. He's going to be dropped over five yards around the area sometimes. But he can't do anything about it and can't be blamed for it.
One thing that's reassuring: you know Arteta will make appropriate tactical adjustments—for example to Zinchenko, or White's roles—to compensate for Holding's slowness.
As for Saliba's injury, I had a hunch it'd be a bit of a problem as soon as his back was mentioned. If you've got an inflamed or bulging disc, and you've got a protective muscle spasm happening, there's not many treatments beyond rest, and stretching and lengthening the affected muscle groups. It all takes time. Saliba might be able to play with analgesia and muscle relaxants, but if he experiences a real spasm, he'll be incapacitated. And if it's anything worse than that …
You'd expect Saliba to be a bit of a roll of the dice for the remainder of the season. He's a big, strong lad who's been getting stronger year by year. I assume they'll have him absolutely thrashing his core in the summer, which you can hope will help stop recurrences.
