Rob Gronkowski missed his second straight game this week and his third out of his past four. His ankle is bothering him, and his back keeps flaring up.

It didn’t take long to see Sunday that the New England Patriots could have used the star tight end against the Tennessee Titans, whose first-year head coach, Mike Vrabel, played under Patriots coach Bill Belichick for eight years.

The Titans were prepared for this one, as they proceeded to smother the Patriots’ quick-hitting, Gronkowski-less offense by manhandling their running game (19 carries for 40 yards) and hurrying Tom Brady six times, sacking him three.

In the end, with Brady completing only 21 of 41 passes, the Patriots’ offense could muster a measly 284 yards in a 34-10 defeat that improved the Titans’ record to 5-4 and gave Vrabel the first signature win of his regime.

It also gave the Titans, many of whom have ties to the Patriots, some room to gloat. Along with Vrabel, cornerbacks Malcolm Butler and Logan Ryan are former Patriots, and so is running back Dion Lewis, who couldn’t wait to pile on.

“It’s a real sweet win, you know, especially when you used to be there and they didn’t want to bring you back,” Lewis chirped. “So, definitely real sweet.”

Lewis later told NFL Network’s Mike Giardi that this one was “personal.”

“That’s what happens when you go cheap,” Lewis added. “You get your ass kicked.”

He also tweeted this:

Now, Lewis’ anger at the Patriots’ decision to forego signing him to a second extension last offseason is understandable. He is a good football player, one with a valuable skills in today’s NFL. A plus receiver out of the backfield with an elite knack for making people miss, his ability to create extra yards both on runs and passes gave the Patriots’ efficient, quick pass-heavy offense a big-play element.

But at 28 years old, Lewis wasn’t about to get the four-year, $23 million deal he signed with Tennessee in March — which includes $11.5 million in guarantees — from the smartest organization in football. Not when the 2018 NFL draft was widely regarded as one of the strongest at his position in years.

And while Lewis’ primary replacement — first-round rookie Sony Michel — was held to only 31 yards on 11 carries Sunday, he has shown some flashes this season. In some very real ways, the combination of he and James White — arguably the team MVP through the first 10 weeks — has managed to replace a decent chunk of Lewis’ overall dynamism, all for a much cheaper price.

One bad game, against a team filled with players and coaches familiar with Belichick, for that matter, doesn’t change that, certainly isn’t an indication that the Patriots are in any sort of trouble. Not when they are still 7-3, with a comfortable two-game lead on the Dolphins in the race for their 10th straight AFC East title.

And that’s the thing to remember about the Patriots. How many times have they been down since Bill Belichick and Brady took over, only to bounce back the next week with an Undertaker-like sit up?

Besides, it’s hard to take Sunday’s loss seriously, especially given Gronkowski’s absence. In the past, the Patriots have fared well without the 6-foot-6, 265-pounder, who is generally regarded as the league’s most well-rounded tight end.

But this year’s team has fewer playmakers around Brady than normal — a situation so dire that they dealt a fifth-round pick for Cleveland’s dynamic (but troubled) Josh Gordon a few months ago — which means Gronkowski’s absence is felt more than ever. At his best, he is the most difficult matchup in football, a man too nimble for linebackers and too big and physical for safeties.

When he’s healthy, he commands the type of attention that gives the Patriots’ other skill players room to breathe, and with the Patriots heading into the bye, Gronkowski will get more time to rest.

Now, it’s also worth noting that it’s no lock Gronkowski will be the same player Pats fans are accustomed to when he returns. Gronkowski is on pace to finish with 52 catches, 796 yards and two touchdowns, marks far off his prime.

And given the Patriots’ renowned cold-bloodedness, it would hardly be a shock if the Patriots moved on from Gronkowski this offseason, as he’s due to tie up $12 million of the salary cap in 2019, the last year of his deal. And truth be told, it’s certainly not a coincidence the Patriots were ready to transition from him last spring, only to have a trade to Detroit nixed by Gronkowski.

Here’s what’s also true: if the Patriots hope to stake claim to the AFC’s top spot — and earn home-field advantage throughout the playoffs — they’ll probably need to win out. Thanks to their head-to-head win earlier this season, the Patriots own the tiebreaker over the Kansas City Chiefs, who currently own the conference’s best record at 9-1. But Kansas City keeps rolling, thanks to one of the NFL’s most exciting offenses in decades, and they face only two teams with winning records in the Rams (9-1) and Chargers (7-2) the rest of the way.

The Patriots, meanwhile, also face two teams with winning records down the stretch in Minnesota (5-3-1) and Pittsburgh (6-2-1). The Steelers game, in particular, looms as a potential shootout, as Pittsburgh boasts the league’s fourth-ranked offense.

The good news for the Patriots is that the Steelers also happen to struggle mightily against tight ends. Guess who else does, too? The other team that likely stands in New England’s way of a third straight Super Bowl appearance, Kansas City.

So yes, if the Patriots are going to achieve their goals this season, they’re going to need Gronkowski back and wrecking defenses, as Sunday’s loss to the Titans shows what can happen when he’s not out there doing his thing.

At this point, it’s difficult to expect the worst for the Pats, who are in the midst of one of the greatest runs professional football has ever seen with Brady and Belichick running the show. Perhaps that’s why so many of Belichick’s former coaches and players — like Lions head coach Matt Patricia a month ago, or Lewis on Sunday, for example — often seem to be so excited to beat their former leader.

They know, first-hand, that you’d better get excited about winning battles against the Patriots. Because winning the war is pretty damned hard.

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