About a month ago, the notion of adding Yu Darvish seemed to be something of a luxury for the Dodgers. After all, not only had the Dodgers emerged as the best team in baseball, they had entered the season with the most pitching depth in the game.

But then Clayton Kershaw was sent to the DL, a place where Rich Hill, Scott Kazmir and Hyun-Jin Ryu have resided at times this season — and where they have been placed often throughout their careers.

In fact, they lead baseball with 34 disabled list trips, as Mike Petriello noted. Now some of that was by design as they accumulated high-upside, high-risk starting pitching depth, but they certainly weren’t counting on Kershaw missing significant time.

And now we might also have to add Alex Wood to our watch list.

While Wood was effective in his last outing — he starts again Wednesday versus the Diamondbacks — he has also recently endured his worst outings of the season, including surrendering nine runs on July 21 against the Braves. Wood has allowed only four or more runs four times all season, and two of those outings have occurred in his last four starts.

And his velocity is trending down, which raises something of a red flag:

He’s still throwing harder than he used to, but not as hard as he was earlier in the season.

Something else is also trending down: his release point. Consider his vertical release point, via Baseball Savant Statcast data:

April-May: 5.52 feet

June: 5.42 feet

July-present: 5.47 feet

Now maybe the arm slot change is part of a mechanical change but it can also be an indicator of injury or fatigue.

Alex Wood survived his bullpen session. He made a mechanical adjustment and the life returned to his fastball, he said. — Andy McCullough (@McCulloughTimes) August 6, 2017

Wood’s velocity dip has been noticed, reporters are asking questions, including Andy McCullough of the Los Angeles Times.

Is Wood fatigued?

“There was a little fatigue,” [Dodgers manager Dave]Roberts said. “He wants to go through the next couple days with his postgame workouts and see where it goes.” After the game, Wood vouched for the health of his left arm. But he admitted that his body felt winded, especially after flying from the West Coast to Atlanta for this trip.

Wood’s performance has declined by month, too.

His K-BB mark was 36.6% in May when he really began to open eyes, and it dropped to a still elite mark of 28.1% in June, and it dropped further still (22.6%) in July. Maybe it’s not injury or fatigue related. Maybe it’s just regression, or the cold hard reality that he is not Kershaw or Sale. But it would make some sense if Wood is fatiguing. He has pitched 104 1/3 innings this season, after tossing 60 last season in his return from an elbow injury. He’s the type of arm teams with nothing to play for, and even teams with something to play for, might be cautious with.

Roberts was asked about the possibility of Wood missing a start. He did not rule it out. Wood expressed to reporters he does not feel he needs a respite — but trusting a player about whether he needs rest or be taken out of competition is often dubious.

It seems like Wood could benefit from a break. For a team that has manipulated the new 10-day DL as well as any club, it would not surprise to see Wood land there, particularly with the Dodgers enjoying 100 percent division odds and playoff odds, according to our postseason projections. The Dodgers have an absurd 15-game lead in a division entering play Wednesday, and this is division that at the moment includes the National League’s No. 1 and No. 2 Wild Card teams.

The Dodgers might be a historically good club, but to be a historically good club, to navigate through the more random and luck-depended postseason, having as many front-line starters available is not just a luxury but a competitive advantage.

Maybe Wood is fine and will continue to be excellent. We’ll learn more tonight and in the coming weeks. Kershaw should be fine, but, hey, it’s pitching. We’ll see. But the idea of pitching depth is fleeting, it is something of an oxymoron. Even the Dodgers, the team with the most starting pitching depth entering the season, might need more of it. And the Dodgers seemed to be thinking in such a way, as they added one of the two premium arms available at the trade deadline. Darvish is seeming less like a luxury and more like a necessity for team with world championship and history-making aspirations.

The Dodgers have perhaps built the best team, at least best regular season team, we have seen in several years. But the nature of the game, the nature of pitching, makes even the game’s best clubs vulnerable. The Dodgers ought to be cautious with Alex Wood.