3 reasons the Dodgers can catch the Diamondbacks and 2 they may not

Can: The Dodgers’ offense is in a class of its own

When you look at these two teams’ position players against one another on a leaderboard, you see a relatively small gap in overall fWAR (although LA does come out ahead). However, a deeper look suggests that the gap between the two offenses once you scrape out defensive contributions (which are still very important as mentioned before) is bigger than that.

The Dodgers’ team wRC+ is significantly higher than Arizona’s, as is their team ISO (a power measuring metric), walk rate, and run total. All of this is despite the fact that Arizona has been significantly “luckier” on balls in play -- their team BABIP is much higher that the Dodgers'.

A lot of this points to the Diamondbacks playing over their heads a bit and the Dodgers underperforming a bit, which makes some sense. Max Muncy struggling to hit above .200 for three of the past four seasons certainly isn’t helping, but Mookie Betts is having some decidedly mediocre luck from a BABIP perspective yet again and James Outman is having some real rookie growing pains after a hot start. Plus, the Dodgers having Miguel Rojas’ sub 40 wRC+ over a significant number of plate appearances both isn’t helping the overall picture and probably isn’t indicative of what the future looks like.

Look, if the Diamondbacks continue to have half a dozen guys in their lineups with .350 BABIPs the rest of the way, then yeah ... the Dodgers are in trouble. However, some of that luck is bound to come back to earth, especially with how young some of those guys are. The Dodgers have a ton of guys on offense with track records of being elite while Arizona does not.

Can't: The Dodgers and Diamondbacks have some very different trade deadline restrictions that could favor Arizona

Both teams have some very similar needs with the trade deadline approaching. Both teams have bullpens that are difficult to trust. Both teams, to varying degrees, would like to add some depth to their starting rotations. Unsurprisingly, that's also the shopping list for virtually every contending team across baseball because one can never have enough pitching as arms have been dropping left and right this season.

The Dodgers, however, may be restricted with who they can trade for because they “probably” want to shed some salary already for luxury tax/Ohtani pursuit purposes, and taking on a significant amount of salary could create some issues. They won’t stand pat in all likelihood, especially with the bullpen, but restraint could be in the cards. 

Meanwhile the Diamondbacks, who do not have the minor-league depth the Dodgers have, have every reason to go all in here. Opportunities to topple the Dodgers in the division do not come often and they have some clearly defined needs with enough prospect/player capital to go get a couple higher-end options without having to worry about being financially hamstrung.