This was supposed to be the year that Nicki Collen got Baylor over the hump. The Bears had their deepest team since Kim Mulkey left for LSU and opened the season with an undefeated non-conference campaign. Baylor peaked at No. 4 in the AP poll.

But things have taken a downturn since then. Baylor's currently just 7-6 in Big 12 play and has fallen down to the No. 21 spot in the latest AP poll. So, what's going on with the Bears?

What's gone right so far

Before we talk about what's going wrong, let's first acknowledge that this is a talented basketball team that currently sits 18-6 on the season. Despite being just one game over .500 in Big 12 play, the team is sixth out of 14 teams in the conference and is almost certainly heading for an at-large bid in the NCAA Tournament barring a monumental collapse. This has been a good season. So many programs would kill for Baylor's success.

Per Her Hoop Stats, this team ranks 24th in the country in net rating and has been one of the most efficient teams in the country, ranking 35th in field goal percentage. The team's also played some incredibly selfless basketball, ranking fifth in assists per game and eighth in assisted shot rate.

On an individual level, Sarah Andrews is shooting well from deep, knocking down 37.1 percent of her three-point attempts, while Bella Fontleroy is shooting 40.2 percent from three. Aijha Blackwell continues to be a strong rebounding threat, averaging 8.0 per game. Dree Edwards and Jada Walker both average over 1.5 steals. Like I said, there's a lot of good here.

What hasn't gone so well

But that "good" has faded a little now that conference play is here.

The Bears have a +4.1 net rating in conference games, which is good for fifth in the conference, but that pales in comparison to, for example, West Virginia's league-best +20.9. So, what's going on there?

One big issue has been an inability to defend the paint. Big 12 opponents are averaging 32.9 points in the paint per game against the Bears, the fourth-highest mark in the conference behind Houston, UCF, and Texas Tech.

We really saw that issue in Baylor's surprise loss to BYU. The Cougars have Lauren Gustin, one of the best interior bigs in the country, and she just completely ate the Bears up inside, scoring 23 points on 9-for-14 shooting and grabbing 16 rebounds, including four on the offensive end.

The Bears just don't have the size to match up with these kind of teams. Dree Edwards and Darianna Littlepage-Buggs are good bigs, but neither are taller than 6-foot-1. Baylor's tallest players just aren't seeing the floor. 6-foot-7 Lety Vasconcelos has played the second-fewest minutes on the team while 6-foot-3 Madison Bartley, the second-tallest player, never really found her footing and is currently dealing with a lower back injury.

That's left the Bears susceptible inside. Opponents shoot 66.5 percent at the rim, which is 9.4 percent above the Division I average. That's only gotten worse in conference play, as the team is allowing opponents to shoot 68.4 percent at the rim over the past 10 games.

Until Baylor can figure out a way to slow opponents down inside, they're going to keep losing games they shouldn't lose like the BYU game. They let Taiyanna Jackson score 27 in a loss to Kansas. They should have been able to beat Kansas State since elite center Ayola Lee was injured, but they let her replacement, Eliza Maupin, go 6-for-6 from the floor for 16 points.

And this is an issue without a short-term fix. If Collen thought Vasconcelos was ready to play heavier minutes, she would be. Getting Bartley back might help some, but she just hasn't been the player she was at Belmont, which is a whole other issue. Bartley has averaged 1.2 points per game in her five Big 12 games. After putting up 14.1 per game at Belmont last year and shooting 51.3% from the floor, I really thought Bartley would be a Caitlin Bickle-esque presence on this team, but even when she was healthy, that never happened. And this team really, really needed someone like Bartley, who theoretically was a versatile big who could shoot and play the four but who could also give you some key minutes inside.

The good news is that these defensive issues when it comes to rim protection haven't translated to the other end of the floor, where the Bears have shot 63.1 percent at the rim in conference play. Sarah Andrews is struggling to finish at the rim, shooting just 47.1 percent in Big 12 play, but Edwards, Littlepage-Buggs, and Fontleroy have been elite there, each shooting over 70 percent.

Offensively, the Bears have the talent to pull things together and win any game they play, but, well...you know the adage: defense wins championships. And right now, Baylor's interior defense isn't going to win the team any championships.