There’s a chance the American League playoff field could feature three 100-win teams, but that doesn’t mean each club isn’t without its flaws.

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Even the mighty Boston Red Sox, whose 107 wins entering Thursday are the most by a major league team since the Seattle Mariners won 116 in their historic 2001 season, have a glaring weakness as the start of the postseason approaches.

Here are those problem areas that could affect each AL playoff team on their quest for a World Series title.

5. Boston Red Sox -- bullpen

For those who follow the Red Sox, this comes as no surprise. Nearly all season, Boston’s bullpen has been a question mark, despite a 3.60 ERA as a group that ranks fourth in the AL. The Red Sox have no clear setup option ahead of closer Craig Kimbrel, with journeyman Ryan Brasier and the inconsistent Matt Barnes most often getting the call. Boston has been able to win so many games by outslugging its opponents, but in a tight playoff contest, somebody is going to have to step up out of the bullpen. The team has a wealth of starting pitching, so expect a member of the rotation to be shifted to a relief role with the chance to make a difference.

4. Cleveland Indians -- lack of quality competition

The Indians are as well-rounded a team as any in the field, yet they will have the fewest wins of the bunch. How is that possible when the AL Central includes three teams that will finish with less than 70 wins? A 23-31 record against teams above .500 has been a black mark on Cleveland’s third straight division title. The Indians have played .500 ball throughout the final month of the season, but their primary bullpen issues have been resolved with a recent return to form by Cody Allen and sustained health from Andrew Miller. It won’t be easy from the start for Cleveland, which will travel to Houston to face the Astros in the AL Division Series.

3. Houston Astros -- history

Speaking of the defending champions, here’s yet another well-rounded team with few clear weaknesses on paper. However, history is not on the Stros’ side. Not since the New York Yankees won three straight World Series from 1998-2000 has a team won back-to-back titles. The Chicago Cubs fell flat in the National League Championship Series last year, and each of the four champions from 2012-15 failed to even make the playoffs the year following their World Series win. Left-hander Dallas Keuchel famously proclaimed in spring training, “We’re not the Cubs,” but now is the time for Houston to prove that against the unpredictable nature of baseball’s playoffs.

2. New York Yankees -- injuries

The Bronx Bombers are back, entering Thursday with 256 home runs as a team this season, fifth most all time. But the injury bug has wreaked havoc on the Yankees in the last month. Closer Aroldis Chapman just returned from the disabled list after missing nearly a month with left knee tendinitis, and while Aaron Judge has been back from the DL for two weeks, he still hasn’t hit a home run since sustaining a right wrist fracture in July that was slow to heal. New York also recently received a scare with shortstop Didi Gregorius, though he has been cleared to resume baseball activities after tearing cartilage in his right wrist. Headed for a one-game, wild-card playoff, the Yankees need to be firing on all cylinders to advance to the ALDS. One player less than 100 percent could make all the difference.

1. Oakland Athletics -- no true ace

We know the A’s will be the Yankees’ opponent in that one-game playoff, but who their starter for the game will be is a question mark. With southpaw Sean Manaea out for the season, Oakland manager Bob Melvin has no clear choice and has even indicated that he could utilize a bullpen-game strategy for the contest. Relief pitching has been one of the surprising A’s strengths this season, but can they hold the Yankees at bay for a full nine innings? The stakes will be high when we find out.

--Kyle Brasseur, Field Level Media