Examining the Defense: Ball screens and zone

Michigan-79-Penn-St.-71-3-597x398[1]Michigan’s defense is the primary concern after a frustrating five game stretch. The Wolverines have seen their offensive production hit occasional snags but their defensive performance has plummeted consistently. Most recently, the league’s worst offense, Penn State, found great success against Michigan, with its second most efficient offensive performance of the the Big Ten season.

After watching some film, here are some thoughts on Michigan’s defense, specifically regarding Michigan’s struggles guarding ball screens and the potential of utilizing a zone defense.

Pick and roll defense is an issue

Penn State seemed to expose Michigan on the pick-and-roll. The Nittany Lions got a number of easy looks on rolls and pops en route to one of their better offensive performances of the season. Penn State utilized ball screens on 38 percent of its logged offensive possessions, far more than any other play type. (Photo: Dustin Johnston)

Michigan’s strategy for defending the ball screen has revolved around slowing down the ball handler. While the approach varies from game to game, Michigan’s bigs are showing on the screen and roll and providing significant help to prevent opposing ball handlers to turn the corner and get into the lane – and then recovering. That approach is working to stop ball handlers from getting into the lane:

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Source: Synergy Sports

The chart above shows ball screen defense specific to the ball handler across the Big Ten with percentage of ball handler possessions on the horizontal axis and points per possession on the vertical axis. The best (low volume, low points per possession) teams are in the upper right quadrant while the worst are in the lower left.

However, eliminating production of pick and roll ball handlers has come with a consequence. Michigan’s help defense on the backside has been lacking and roll men are killing the Wolverines. Here’s the same chart but for roll men:

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Source: Synergy Sports

Michigan goes from one of the best teams to one of the worst.

The big man that shows, or hedges, the screen is meant to stop the ball handler until his original defender recovers – then recover back to the paint. If the roll man slips the screen, it is absolutely necessary that help defense covers the roll man. Michigan’s problem is two fold: often times the big man is late recovering, but even when he’s not the help defense hasn’t been consistent.

The beauty of ball screen is that it forces defenses to make a choice – usually taking a gamble. It’s extraordinarily difficult to take away all options effectively – the roll man, an open jumper and a lane to the basket around the corner and a lane to the basket while rejecting the screen.

Here’s a closer look at a (rather extreme) example of what’s going wrong with Michigan’s ball screen defense.

This play is slightly different because it’s a double screen but most of the concepts are the same. Stauskas gets screened and McGary has to step up and show on the ball handler. Robinson goes with the first screener, who pops to the wing.

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McGary’s show is fairly soft but there’s little concern of Nick Collela driving the lane (although he did at one point for an and one) and McGary eliminates the potential of a shot.

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Here’s where things begin to fall apart. Sasa Borovnjak is rolling into the paint and there’s not a single Michigan player in the same zip code.no help073

Rather than providing help, Tim Hardaway Jr. actually takes a step toward his man – Ross Travis, a 14% three point shooter – on the wing.

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By the time Hardaway starts to come to the lane with help, Boronvjak is already catching the ball and ready to lay it in.

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Here’s full motion:

Here’s the same action again – with both Stauskas and Hardaway failing to provide any help in the lane.

There is merit in the strategy. Not only does better help make a difference, Michigan has a couple of bigs that are usually pretty good at disrupting with the hedge. Mitch McGary is great moving his feet on the perimeter, Jordan Morgan is fairly mobile and Jon Horford has solid length to defend passes. It should come as no surprise that Michigan forces pick and roll ball handlers into more turnovers than any other league team.

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Source: Synergy Sports

With sound help defense in the back, the strategy should work and here’s a solid example. Burke is screened on the wing and McGary shows to provide help.

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Burke could probably do a better job fighting through this screen, and McGary probably could have done a better job hedging as DJ Newbill still nearly turns the corner. But luckily for Burke and McGary – their three teammates are all firmly positioned to provide help. All three help defenders are in or near the paint and ready to help. Robinson is the first key as his presence on the elbow forces Newbill to turn back into McGary and Burke.

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As Newbill crosses over, he meets McGary and Burke recovering. There’s room for a pass to pass between Burke and McGary but Borovnjak isn’t open rolling to the basket because Michigan’s other two help defenders are at the ready. Hardaway and LeVert both have a foot in the paint and are ready to take away the the pass to the rolling big man.

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Newbill realizes that fact and turns right back into Burke who ties him up for a turnover. Here’s the full motion:

Zone probably isn’t the answer

A common refrain among Michigan fans whether at the bar or in our open thread is: if Michigan can’t check anyone in man-to-man, then why doesn’t it just play zone? The problem is that Michigan’s zone defense hasn’t been all too effective.

Defense %Poss Poss. Points PPP Percentile
Man 93.10% 1518 1205 0.794 72%
Zone 6.90% 113 102 0.903 47%

That’s a small sample size, with just 113 possessions in 26 games, but the results aren’t generally encouraging.

Michigan has only played zone for 26 possessions in Big Ten games and the Wolverines have surrendered 27 points – 1.04 points per trip.

Michigan has played predominantly 2-3 or 1-3-1 zone looks with a couple possessions of 3-2 sprinkled in. The 1-3-1 and 2-3/3-2 have very different goals. Michigan’s 1-3-1 zone is primarily designed to force turnovers while the 2-3 is more to limit penetration.

A majority of those zone defensive possessions came against Ohio State (12 in two games), Illinois (5) and Michigan State (4). The fact that Michigan was playing from behind in most of those games before it switched to the zone makes it pretty clear that John Beilein considers moving to the zone something of a desperation move.

Michigan’s youth has been exposed in man-to-man sets quite a bit and it’s hard to deny that the roster lacks a lot of experience in the post, quickness at some of the guard spots and has struggled to consistently make defensive rotations (as evidenced above). But zone defense requires practice too and experience can be just as detrimental in a zone defense.

Other than a couple of non-conference games – the 1-3-1 against Pittsburgh stands out – the zone hasn’t looked particularly effective and the numbers back that up. There are a lot of teams in the Big Ten that have great shooters – see Jordan Hulls in the corner at Assembly Hall – and know how to get open looks. The fact that Michigan actually forces more turnovers on man-to-man (16.4% TO Rate) than zone (13.3% TO Rate) possessions shows that the 1-3-1 trap rarely works and more often than not, Michigan’s zone defense is reduced to hoping opponents miss open jump shots.

However, with a week off and plenty of preparation time before Illinois, it would be a bit surprising if Michigan doesn’t at least experiment with the zone down the stretch.

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