Baseball no longer follows the strict divisional matchup model in September, but this year's schedule provides plenty of fun matchups over the season's final three-plus weeks. If you've been looking for reasons to mark your calendars, then here are a few. MLB.com is taking a look at the 10 most important series remaining on the schedule as the '18 season winds to a close.
One rule: Each matchup between two teams can only appear once. So, for example, the Braves and Phillies have two remaining series, and they're, of course, both huge. But for variety's sake, we'll only include one of them.
And a couple of other guidelines: When there were two meetings, we erred on the side of including a four-game series over a three-gamer. There was also some attempt to spread them out, to give you something to watch just about every night for the rest of the season rather than having too many series during a single weekend.
10. A's at Rays, Sept. 14-16
It has seemed that the American League Wild Card race was three teams for two spots for a while now. But Tampa Bay is lingering on the periphery, eight games behind Oakland and 2 1/2 behind Seattle. The Rays have been one of baseball's hottest teams since late June, playing at a 102-win pace over their last 62 games. The odds are against them, but if they're going to make a stand, it happens here.

9. Astros at Red Sox, Sept. 7-9
It's not likely, but it's possible that this series could affect home-field advantage in the AL. That's not why it's here, though. Instead, it's a very tough series for the defending champs, whose division lead still is pretty small. If they have a tough time in Boston, the AL West race could tighten up. If not, they're in good shape. The Astros follow this series with a trip to Detroit, a three-series homestand (admittedly including some good teams), and a trip to Toronto and Baltimore.

8. Cardinals at Cubs, Sept. 28-30
On a list of the most fun remaining series, this one might rank higher. But the NL Central race is not as tight as some of the other races we're checking in on, and there's a decent chance it could be decided by the season's final weekend. But … what if it's not? There's not much that's better than Cubs-Cards with something on the line, and it's still possible there could be a ton on the line when these old rivals get together at Wrigley.

7. A's at Mariners, Sept. 24-26
The Mariners are in a tough spot, but they'll have their chances. They play the Yankees for three games this weekend, and the A's for three late in the month. Besides that, they have one series against Houston, and their other four come against non-contenders. So there is a chance for them to catch up enough that this could be a huge series in the season's final week. Plus, they're at home.

6. Dodgers at Cardinals, Sept. 13-16
When the Dodgers arrive at Busch Stadium, they'll be the first contender the Cardinals have seen in three weeks. It will also be the end of a three-city trip for L.A. Mostly, though, it's a matchup of two teams that are trying to maintain traction in divisional and Wild Card races -- not to mention two teams that have seen quite a bit of late-inning drama.

5. Brewers at Cardinals, Sept. 24-26
Depending on how the other races shake out, this could be a battle for home field in the Wild Card Game. It could also be a play-in for a chance at the division title in the season's final weekend, or a fight to stay in the Wild Card Game. We know this much, though: It's likely to be entertaining. Few teams consistently play weirder games than the Brewers, and the Cards have had their share, too.

4. Phillies at Braves, Sept. 20-23
If it feels like these teams haven't played each other in forever, well, they haven't. It's been a weird race, with lots of scoreboard watching and no head-to-head games in months. They played 12 times in the season's first eight weeks, and then not again. But they'll get to know each other extremely well at the end of the year -- they play seven times in the season's final 11 days. This one gets the nod over their season-ender because it's a four-game set, and because it begins a rough eight-game trip for the Phillies. They go to Denver from Atlanta.

3. Dodgers at D-backs, Sept. 24-26
You're going to notice a trend in the top three entries. There's just no race better than the NL West. It's close. It involves three teams. Those three teams play each other a lot down the stretch. And there may not be any net below them, if the Cardinals and Brewers play well and eliminate the fallback option of the Wild Card Game. As of now, these teams are second and third, which is why it ranks third. The Dodgers have had fits with the D-backs all year, and they'll need to overcome that to win the division.

2. D-backs at Rockies, Sept. 10-13
Yeah, this is going to be fun. Four games in Denver begin a very tough weeklong road trip for Arizona. These teams meet again barely a week later in Phoenix, but the four games at altitude win out by a hair over the three in the desert. It's worth noting that Arizona's schedule is absolutely brutal down the stretch, with only one series remaining against a non-contender -- the final three games in San Diego. Between now and then, it's home for the Braves, at Denver, at Houston, and home for the Cubs, Rockies and Dodgers. Goodness.

1. Dodgers at Rockies, Sept. 7-9
The fun starts soon. This one wins out by a hair for a few reasons. First, the Dodgers will be without Kenley Jansen, who will skip the trip due to potential risk to complicate his heart condition. It's also the start of a three-city trip for the Dodgers, as well as a stretch of 13 straight games without an off-day. The teams have their pitching lined up, with Clayton Kershaw starting Friday for L.A. and Kyle Freeland on Saturday for Colorado. It should set the tone for a wild closing stretch in baseball's most competitive division.