Gronk is integral to the Pats playoff chances.
"Gronk," who broke his arm in Week 11, took part in practices leading up to the Pats' game against the Jacksonville Jaguars but was ruled out for the game. While it's uncertain whether he'll play against the Miami Dolphins in Week 17, Gronkowski looks like a good bet to be healthy by the playoffs given his initial four-to-six week prognosis.
The Pats will need him for their postseason run, too—with Gronk, the Pats offense (which has stumbled out of the gate in back-to-back games) becomes much more difficult to defend.
How exactly does Gronk's return change things for the Patriots offense? Let's take a look.
No More Welker/Hernandez Double-Teams
The 49ers were able to get pressure by rushing just four (thanks in large part to dynamic interior rushers Aldon and Justin Smith) and leaving seven in coverage, four of whom were often dedicated to Welker and Hernandez.
Naturally, very few teams can get pressure with just four rushers, which is why the Pats offense has fared just fine in their five regular season games without Gronk.
But several playoff teams can get enough pressure from their defensive line to pose problems for New England's offense. In fact, the Pats' projected matchups in the first and (if they make it) second round, the Cincinnati Bengals and Denver Broncos, rank first and second in the NFL in adjusted sack rate.
Here's a look at the kind of problems a good defense can cause the Gronk-less Pats.
It's 3rd-and-goal, with the Pats looking to tie the game early in the second quarter. New England lines up in the shotgun with 11 (one RB, one TE) personnel and three WR. San Francisco counters with a 3-4, rushing their defensive linemen and Aldon Smith off the edge.
The 49ers drop seven back but leave outside receivers Deion Branch and Brandon Lloyd one-on-one in press coverage with their CBs. They leave NaVorro Bowman in a soft underneath middle-zone and double-team Welker and Hernandez.
The guys in red circles cover Welker, and the ones in green circles cover Hernandez.
Carlos Rogers (No. 22) settles inside on Welker, forcing him into safety Donte Whitner over the top. Notice the press coverage on Branch on the outside and his failure to get any separation.
Finally, in the orange circle, 49ers DE Ray McDonald has inside leverage on Dan Connolly.
Hernandez has a step on LB Patrick Willis on the inside slant, but S Dashon Goldson has him over the top. Without Gronk, there's really no one else on the field the safety has to worry about in the red zone, so the defense can commit him to Hernandez without hesitation.
With no one able to get open (though Lloyd arguably got held, but that gets missed all the time on both sides) and Connolly getting blown off the spot, Brady takes the sack from McDonald to force a field goal.
With Gronk in the game, not only would the Pats have had the league's best red-zone threat, but the 49ers wouldn't be able to double Hernandez and Welker. Gronk's presence forces the defense to single-cover one of the Pats three biggest weapons, making them a much more difficult team to defend.
The Run Game Brings Back a Mauler
I've gone over how Gronk helps the Pats' run game before. And while it's true that Pats feature back Stevan Ridley (18 rushes, 84 yards in Week 16) hasn't had a huge drop-off since Gronk's injury, things have been a little tougher on the Pats' power running game against elite defenses in tight spots.
In the article linked above, I got a little somewhat-deserved flak for diagramming a run play in which Gronk mauled a safety instead of one in which he beat a DE or LB. Gronk had 60 pounds on the guy, so it's fair to wonder why I'd pick that play.
But here's a play in which the other TE, Hernandez, didn't blow a safety off the block. In fact, he was the one who got blown up, and it contributed to a goal-line stuff by the 49ers.
The Pats line up in the big-I with Hernandez and Daniel Fells as the TEs on either side of the line. The 49ers send eight to the line with three LBs up in the box. It's pretty obviously a run play, so all that matters at this point is who wins the point of attack.
The call is a slash off the left tackle, and the hope is that Hernandez can seal off the edge against Goldson for an easy TD.
The play starts off all right—both Hernandez and LT Nate Solder (both in orange circle) have engaged with high pad levels, but the Pats appear to have the edge sealed. It looks like Ridley will be able to scamper wide left for the easy score.
Ridley has TE Michael Hoomanawanui (lined up at fullback) ahead of him with only the MLB (five yards deep in the end zone) unblocked to that side. All he needs is for Hernandez to hold that point of attack against the safety.
Here's where having Gronk to make that block would have helped. Hernandez (orange circle) gets blown off his spot right into Ridley's running lane, forcing the RB (green arrow) to bounce it back inside.
A competent blocking TE on that side would have held that point of attack. Gronk would have mauled Goldson into the third row. But Hernandez, a fantastic receiving option but a middling blocker, lost the edge against a safety on the play.
Hernandez is now completely out of the play, blown back by the safety. He ends up getting thrown back several yards as he and Goldson wind up on the ground (and scuffle a bit at the end of the play).
Meanwhile, Ridley runs right into Aldon Smith and gets stacked up by the 49ers line.
The Pats converted on fourth down, rendering this play largely irrelevant to the outcome of the game, but it still speaks to the Pats' need for Gronk in power-running situations, especially on plays when they need to set the edge.
Without Gronk, the Pats have been leaning heavily on their three WR, 11 personnel sets. According to Mike Reiss of ESPNBoston, the Pats initial game plan against the Jaguars in Week 15 originally centered on 12 personnel (one RB, two TEs)—10 of their first 11 snaps came from that package.
But after two INTs came from plays that began with their two-TE package, the Pats spent a large portion of the game (34 of 75 snaps) in three-WR formation.
With Gronk, the Pats will likely rely more heavily on the 12 personnel, which causes nightmare scenarios for opposing defenses as they get caught too slow in their base and too light in their nickel. I detailed in the article I linked above how Gronk's dual receiving/blocking capabilities make it easy for the Pats to disguise their intentions.
That, plus the Pats' tendency to lean on the hurry-up when they get a mismatch, allows New England to exploit defensive matchups regardless of defensive packages.
In short? A healthy Gronk makes the Pats tough to stop. With the playoffs around the corner, New England needs him now more than ever.