Ronald Acuna Jr. of the Atlanta Braves has been the NL MVP favorite practically all season.

Acuna's MVP odds never got to Shohei Ohtani levels, but he looked like a virtual lock to win just a few weeks ago. In early August, Acuna was -1000 to win the award. That's implied odds of about 91 percent. He was -500 a week ago.

There was a massive shift over the past week.

With August winding down, Acuna doesn't lead the MVP race anymore. Mookie Betts of the Los Angeles Dodgers became the favorite over the weekend. At BetMGM, Betts is -145 to win MVP. Acuna is +125, the first time he has had a plus in front of his odds in months.

There will be MVP intrigue in September.

Mookie Betts is the new MVP favorite

Betts has been having a very good season, then had a red-hot week. Betts went 16-of-26 for a .615 average over the last week. He hit a homer and stole two bases as well. Acuna hasn't been bad, but Betts has been tremendous lately.

Here's how the numbers look with about a month left:

Acuna: .330 average, 28 homers, 74 RBI, 115 runs, 59 steals

Betts: .315 average, 35 homers, 93 RBI, 110 runs, 10 steals

Betts has 7.4 wins over replacement and Acuna has 6.3. For what it's worth, the Braves have the best record in the majors at 84-45 and the Dodgers are second in the NL at 80-49.

It seems impossible that a player could finish with 35 homers and 70 steals for the best team in baseball and not win MVP, but that's a possibility for Acuna now.

Who will win MVP?

Acuna was so good for so long this season that we might have gotten too used to it. Betts is the hot item, the shiny toy in the race. It's not exactly voter fatigue, but the same concept applies. It got old talking about how great Acuna has been all season. The same goes for the Braves, who are 12.5 games up in their division. Betts has been better the past month (he's hitting .464 over the last 30 days) but Acuna has been great too. He has been great since April. But recency bias might be kicking in a bit.

Acuna was such a heavy favorite through July and most of August that BetMGM had offered odds on anyone but him winning NL MVP. But then Acuna's odds started moving last week and Betts overtook him as the favorite. It's a pretty shocking shift, especially considering that Acuna hasn't been playing poorly.

There's a little more than a month to go in the regular season. The numbers between the two players are similar. Even though Betts has a slight lead in the odds, it could still go either way. Acuna can still win the award, but he better have a great September.