Mizzou’s transition at defensive coordinator is off to a pretty smooth start.

After a pair of back-to-back shutouts to open the season, Missouri football kept dynamic quarterbacks from Boston College and Vanderbilt quiet enough to get the Tigers over the line and off to a 4-0 record. MU ranks seventh in the country for total defense, has forced the 11th-best rate of stops on third down and has both a top-20 pass and rush defense.

But Missouri’s biggest tests are upcoming. Texas A&M is next on deck. A trip to Alabama awaits at the end of October.

And Mizzou hasn’t quite hit full speed yet.

More: Missouri football tumbles out of top 10 in coaches poll after double-OT win over Vanderbilt

More: How have opening four games impacted Missouri football’s College Football Playoff chances?

Here are three positions we think that Missouri’s defense can tweak or improve during its first idle week of the season:

Let the pass rush loose

Missouri was a blitz-heavy team last year, but situational factors have kept that to a minimum through defensive coordinator Corey Batoon's first four games.

But when you’ve got somebody as impactful as Johnny Walker Jr. at the edge position, it might benefit the team to let him loose a little more.

Johnny Walker Jr. was an elite QB hounder for MU last season, but either by design or by situational need hasn’t quite hit those heights yet this year. His lone sack so far this season came against Boston College.

Last season he rushed the passer, per PFF, on 62.4% of his snaps. This year he’s rushing the edge 46% of the time, a significant drop in the primary trait that made him the Cotton Bowl defensive MVP.

Zion Young has been an impressive addition at the field end position, where he’s used sparingly as an edge rusher and instead has played a vital role in keeping the mobile opposition QBs contained to the pocket. Eddie Kelly had his best game on the edge as a Tiger against Vanderbilt. MU’s defensive tackles have been stout.

The Tigers’ front, for the most part, has been up to the task at hand.

Now, as the schedule gets a little deeper and the playmakers generally a little better, letting Walker make an impact could be a game-changer.

MU must figure out coverage busts

No need to pore over the analytics to come up with this observation.

Missouri has had some seriously costly moments on obvious lapses in coverage.

The mobility of both Vandy’s Diego Pavia and BC’s Thomas Castellanos has a lot to do with Missouri’s coverage breakdowns in Weeks 3 and 4. When the game plan, at least in part, emphasizes containing the quarterback in the pocket, it’s understandable — if not advisable — for some eyes in the secondary to fleetingly turn that way.

But, those fleeting moments caused Missouri to directly give up three total touchdowns — 67-, 65- and 38-yarders — between those two QBs, which ended up making both games cagey affairs.

Here is the issue: The dual-threat QBs don’t stop coming.

Alabama’s Jalen Milroe is every bit as good on the ground as he is with his arm; South Carolina’s LaNorris Sellers burned LSU for 75 yards and two rushing touchdowns; Arkansas’ Taylen Green has run for 325 yards and four scores in four games. If A&M opts for Marcel Reed over injury-ridden Conner Weigman, there’s another mobile QB on the docket.

Almost everyone in this league playing the position is athletic enough to make a draw or two a concern.

Mizzou’s discipline at DB can’t leap out the window the moment the quarterback threatens to hustle. Two straight weeks with busts is an emerging pattern. The Tigers need it to not become a trend, or they will lose games over October and November.

Establish cornerback depth

Dreyden Norwood has been just about every bit as good as the MU coaches billed in preseason.

PFF has charted him as being targeted nine times this season and allowing four receptions. The analytics site has included Boston College’s 67-yard touchdown among those, although that did not appear to be Norwood’s direct assignment more than it was a secondary-wide collapse. Other than that, he’s allowed three receptions on eight targets for … eight yards.

That’ll play.

But the depth at the position is seemingly lacking. Once Missouri gets past Norwood and his starting partner, Toriano Pride Jr., there aren’t many more shared snaps.

Their main backup to date, Nicholas DeLoach Jr., has been targeted six times and allowed five receptions in 51 snaps, per PFF. Ja’Marion Wayne recently returned from injury and played sparingly versus Vandy. Marcus Clarke did not feature against the Commodores, which would seem to indicate that he is not currently in the rotation.

In recent seasons, corner hasn’t been a position the Tigers have rotated at much beyond their starters. But even these snap counts indicate there’s a far-and-away top two and a little hesitancy beyond them.

Drinkwitz has heralded the competitive depth of this team. Before need becomes a must, the Tigers need a third and fourth player to step up at cornerback.

This article originally appeared on Columbia Daily Tribune: Positions Missouri football defense can improve after idle week