It's 5 bad starts. And yes, he should no longer pitch in day games for the remainder of this season. That is, if the team is at all serious about winning.
7.25 ERA in the day, 2.39 at night. And he's got 11 night starts so they split isn't some huge gap. He has allowed as many ER in 5 day starts as he has in 11 night starts (18).
If they want to have him work on day stuff, they can do that at the beginning of next year. Not now.
I have consistently been a huge proponent of putting players in the best position to succeed. This means I want Whitlock in the pen, Verdugo at leadoff, Story at 2B, and Bello in night games only. I remember being incensed when X was first breaking in that they did not put him at shortstop and just leave him there, they just messing around with his positions. That outlook has never wavered in all my years on this board, and I find it extremely frustrating when managers do not do this.
IMO this is fundamentally reactive thinking: if something seems to have broken, you will do
anything to try to fix it, no matter what cascading issues that creates. While you might be right that the choices aren't ideal, the alternatives might be worse.
For example, ignoring the fact that Bello probably can fix this day-game-night-game issue and it's only 8 games over the last couple of years that we're drawing conclusions based on, let's say we
should avoid him in day games. How do you actually make that happen? Do you have another pitcher start on shorter rest? What if that guy gets injured as a result of less rest? Where are you then? Do you plan the whole season ahead of time so he never piches a day game? How practical is that?
Story played his whole career at SS before coming here and was, uh, pretty good. He might not be elite anymore there defensively, but putting him at SS also allows us to field the best offense. But again, let's say it's better for him, somehow, to be at 2B. Where does that leave us? We have to start Chang or Reyes or Kike at SS, which leaves our offense with a guy who's as bad a pitcher at hitting, whereas putting Story at SS allows us to make Chang/Kike a back-up, run Arroyo at 2B the majority of the time, which improves the offense. (Honestly, of all of these complaints, The Story thing baffles me the most. The guy got his elbow reconstructed! If a pitcher had Tommy John, would you say he should stick to sitting on his couch because he was better at that while he was waiting for his arm to heal? No! He'd go back to pitching!)
The Whitlock in the pen thing might end up being true, but I'd also note it's worth trying to get him to sort things out there because a guy who can throw 150 innings is way more valuable to us than a guy who throws 60 or 70. He's also been there because Kluber and Pivetta were so bad as starters and have a track history of being
so bad. I think when Houck and Sale come back it might be Whitlock to the pen, but they don't have that luxury right now, barring a trade for a SP, which I think would be a good call so long as the price isn't too high. They may also keep Pivetta/Murphy in a bulk role, given the success those two have had, and shrink-wrap Whitlock and Houck while they work back up to effectiveness, which would, I think, be prudent. But that doesn't mean I don't think in the long-run it's worth letting those guys try to be starters. They have starter's stuff, they were very effective as starter's in the minors and have had rough seasons but have had success as starter's in the bigs (and their peripherals indicate they've been unlucky), and letting them start gives them the best shot to throw the most innings, which is the best thing for the club.