The Kansas City Chiefs had a fantastic season. They went 14-3 and got the No. 1 seed in the AFC.

Bettors don't think it was that great.

The Chiefs were just 5-11-1 against the spread this season, tied for the second-worst ATS record in the NFL. Leading into Week 18, the Chiefs had a nine-game stretch in which they covered the spread just once.

There can be a big difference between a great season and a great season for bettors, and that's shown with some surprises among the teams with the best and worst ATS records this past season.

Bucs, Chiefs among worst teams for bettors

Here are the teams that finished with more than 10 losses against the spread, according to Covers.com:

• Tampa Bay Buccaneers: 4-12-1

• Chicago Bears: 5-11-1

• Chiefs: 5-11-1

• Indianapolis Colts: 6-11

The Bears losing that many games against the spread was a bit surprising. They were bad, earning the No. 1 overall pick, but everyone figured they'd be bad coming into the season. And they vastly underperformed in regards to the betting market.

The Colts being on the list is no surprise. They were the AFC South favorite before the season and were absolutely miserable in their 4-12-1 season.

Then you get two playoff teams on the list. Tampa Bay went just 8-9 during the regular season after being touted as Super Bowl favorites, so while the Bucs won a bad NFC South, bettors (and everyone who watched the Bucs) knew they had a bad season. Still, 4-12-1 shows that the betting market never got its head around Tom Brady's team being as awful as it was.

We're on a multi-year run of the Chiefs being very good in the standings that matter most, but not covering many spreads. Oddsmakers know that the public wants to back Patrick Mahomes and it inflates the lines accordingly. Keep that in mind for next season.

Who were the best ATS teams?

Some teams were very good to bettors this season. Here were the best teams against the spread:

• New York Giants: 13-4

• Cincinnati Bengals: 12-3-1

• Detroit Lions: 12-5

• Los Angeles Chargers: 11-5-1

• San Francisco 49ers: 11-6

• Pittsburgh Steelers: 10-6-1

Appreciate that Giants' record. It is very, very hard to post a record like that against the spread. Once it became apparent early on that the Giants weren't that bad — or at least able to beat their analytic expectations — then oddsmakers shifted their rankings on the Giants. And they still beat the number 13 of 17 times. The Giants are 3-point underdogs at BetMGM for their wild-card game against the Minnesota Vikings this week.

The Bengals are similarly surprising because they snuck up on nobody after their Super Bowl run last season, but still had a phenomenal 12-3-1 record. It's not often a team loses only three times over the course of a season for bettors.

The Lions and Steelers played well after starting slowly, and bettors catching onto that trend after the ratings dropped for both teams cashed in. The 49ers were simply dominant since late October, and the Chargers kept covering spreads.

There are only 13 NFL games left this season. But it's not too early to start thinking ahead to next season, trying to identify which teams will surprise us with their ATS records.