I’ve had a weird problem when dishing out grades to Milwaukee Bucks players after games recently.

Over and over, guys are tossing out some pretty solid lines. For a guy like Brandon Jennings, outside of his last two games, he’s been shooting better than 40% regularly and handing out more than 10 assists very often. Monta Ellis has been on one of the more efficient offensive runs of his career during the second half of this season. Ersan Ilyasova has been scoring and rebounding very well when he’s been healthy in March and Larry Sanders is a walking double-double when he doesn’t get ejected.

Yet the Bucks have lost six of their last eight games. Pretty offensive numbers can’t always mask a terrible defense. But lately, the Bucks have been in the difficult position of having players succeed offensively while failing miserably on the other end.

Ilyasova was a terrific example against the Hawks on Sunday. Despite failing to hit a three, he had a very passable line of 19 points and 10 rebounds in just 28 minutes. He grabbed six offensive rebounds and made five free throws. It was everything the Bucks could have wanted Ilyasova to do on offense in his first game back after missing Milwaukee’s past three games with a back injury.

This picture could have been taken a few times on Sunday. (AP Photo/Morry Gash)

But on the other end, Ilyasova had significant troubles with Josh Smith. Smith caught the ball in the post and made a first move too quick for Ilyasova to stay with, leading to two easy dunks. He caught the ball in a misdirected pick and roll and was way too fast for Ilyasova to move over and interrupt his path, leading to another easy dunk. Late in the fourth quarter, Smith caught a pass at the top of the key and simply blew by Ilyasova to his left, finished and got fouled for an and-one. Every way Smith wanted to score, he did.

But Ilyasova could hardly come out of the game.

“The problem is, if I try another match-up  then I’m taking Ers off the floor,” Jim Boylan said after the game. “This isn’t Iowa girls basketball. You can’t have a guy on one end and a guy on the other end. Ers battles him, it’s not for lack of effort, let me just put it that way.”

I wish it were lack of effort. Lack of effort can be fixed with some rotation jumbling and a few well placed benchings. With Ilyasova, it obviously isn’t his effort. With Ellis, with Jennings, it’s less clear. We know they give it their all on offense. We love the big assist numbers and Monta’s fourth quarter threes. We see Jennings pressing full court on defense often and Ellis sneaking up on unsuspecting big men for steals.

But when looking at the bigger picture, we aren’t seeing much in the way of defensive results with either of them on the court. Especially late in games.

Once again the Bucks allowed 30 points in the fourth quarter against the Hawks. In six of their past 14 games since the trade deadline, Milwaukee has allowed at least 30 points in the fourth quarter. Over that stretch, Milwaukee’s fourth quarter defensive rating is 119, while the Bucks fourth quarter offensive rating is 109.8.

For some reason, guys aren’t making the commitment on the defensive end. Maybe they’re tired. Maybe they’re too focused on the offensive end to worry about defense. Maybe they just play bad defensive lineups with three guards too often. We cant’ say for sure. But we can say that Milwaukee’s defensive problems, specifically the fourth quarter problems, have quickly become an epidemic that need a cure.

I don’t know what that cure is. In listening to Boylan address the media after another frustrating game that slipped away late Sunday, I’m concerned he might not quite be willing to make the difficult moves he may need to down the stretch. Boylan seems like the ultimate player’s coach. He internalized much of the blame when his guys let a very winnable game slip away. He took the heat for missed box outs and foolish passes. Kudos to him for that.

But he’s got to be willing to make some changes to his late game rotation if guys are either unwilling or unable to play defense successfully, even if it comes at the expense of some of those guys putting up such beautiful offensive nights.