It was a rare occasion where everybody was in sync and nearly everything went as planned.
On the Ravens' first running play in Sunday's loss to the Cleveland Browns, their offensive linemen fired off the line of scrimmage and rolled left in unison, as if they were tied together with string.
Left guard A.Q. Shipley and center Gino Gradkowski latched onto a pair of Browns defensive linemen and took them for a ride. To their right, guard Marshal Yanda sealed off a linebacker. All that prevented running back Ray Rice from reaching the open field was a missed cut block by right tackle Michael Oher on the back side of the play.
The zone run went for 5 yards. It would be Rice's longest gain of the afternoon and was the first of many missed opportunities for the Ravens, who rushed for just 55 yards on 21 carries in the game.
The Ravens have used zone runs since John Harbaugh was hired as coach in 2008, and the frequency rose after they signed fullback Vonta Leach in 2011. But with Rice and fellow running back Bernard Pierce running in place this season, the zone scheme has been scrutinized.
While the Ravens have tinkered with their scheme under new run game coordinator Juan Castillo, who was hired in January, they have been building a zone-blocking running game over the past few years that relies on precision as much as it does power.
"We've been an inside and outside zone team since we got here," Harbaugh said. "When you run this offense, the zone plays are the base plays that you run. And most every team in the league that's running this offense is running those same plays, and we've just got to get good enough to run them well. We've got the guys who can do it."
Zone blocking is a basic concept used by most, if not all, NFL teams to some degree.
Instead of blocking assigned defenders, the offensive linemen and tight ends move together in the direction of the run. Each one blocks any defender who crosses his path, sometimes with the help of another lineman. If possible, he slips off his block and heads downfield to make another.
"It's really not a difficult concept," NFL Films senior producer Greg Cosell said. "You need your offensive line to move in total synchronization. We always joke and say it's elephants on parade. What you're attempting to do is stretch the front side, or play side — the direction in which the play is going — and you need to cut or seal the backside. And somewhere within that a lane will appear."
There are two kinds of zone runs, the inside zone and outside zone, and they work in tandem. On inside zone runs, the blockers knock defenders backward to open lanes between the tackles. On outside zone runs, they move laterally to stretch the defense toward one sideline.
In 2011, Rice, often running behind Leach on inside and outside zone plays, set career highs with 1,364 rushing yards and 12 touchdowns. Last season, he earned a second straight Pro Bowl invitation with 1,143 rushing yards and nine touchdowns.
This season, though, Rice and the Ravens have been nowhere near as successful. They rank last in the NFL with an average of 2.78 yards per carry. According to ESPN, they are on pace to finish with the lowest average since the 1953 New York Giants. Rice has just 259 rushing yards, Pierce 230.
"We've tried different things, but at the same time, it's still the same thing," Rice said. "It's not a different scheme. It's not a different offense. We're running an offense that fits our personnel right now."
In recent years, the Ravens have drafted linemen they felt had the athleticism and lateral quickness to steer defensive linemen toward the sideline or seal off linebackers at the second level.
In the past, Rice displayed the patience and vision the zone scheme requires, along with the balance, loose hips and quickness needed to abruptly change directions and shoot through a hole when it opened. So did Pierce, who was drafted in 2012 because he fit the scheme.
And Cosell said Leach is as good as there is in the league in terms of anticipating where lanes will open on zone runs.
So who or what is to blame? Is it the schemes? Is it the running backs? Is it the blockers?
"Everybody wants one answer to these kinds of questions, and there is never one answer," Cosell said.
The zone-blocking scheme hasn't changed drastically since Castillo took charge of the running game this offseason, but there have been tweaks. The Ravens have used more outside stretch runs, but the backs have been bottled up and the gains minimal.
Last month, some linemen, including offensive tackle Bryant McKinnie, who has since been traded to the Miami Dolphins, privately voiced concerns about the changes, according to sources. And on his way out of town, McKinnie was outspoken in his criticism of Castillo, saying, "Juan wants it done his way," and that "everything should be running more smoothly."
The offensive linemen have often gotten little push on the front side of plays, and they have had trouble sealing off the backside, denying the running backs opportunities to cut back against the grain for long gains. Tight ends Ed Dickson and Dallas Clark, who are not known for their blocking, have been getting knocked back or down to the ground on the edges.
Rice and Pierce, who have both dealt with lower-body injuries, have been indecisive at times and haven't always hit holes.
Injuries also are a factor; starting left guard Kelechi Osemele is out for the season and will have back surgery, while Yanda has not been as dominant after offseason shoulder surgery.
Baltimore Ravens Insider
"The issue is that [defenses] have been playing more downhill and they have been hurt by penetration," Cosell said. "They haven't responded to it well. Combine that with the fact that I think Rice is not running with the same balance and lateral explosion that he has had in the past and I think that's a recipe for a poor running game, which is what has it been."
Cosell said that when defenders shoot into gaps to stop zone runs, offenses must go to different types of running plays in their arsenal, such as power runs with double-team blocking, to exploit their aggressiveness. But other types of running plays have not been working for the Ravens, either.
In recent weeks, the Ravens have used more single-back formations and experimented with zone runs out of the pistol formation in the 24-18 loss to the Browns. Regardless of the formation, for the Ravens to replicate the kind of success they had with zone runs in years past, they need the blockers to work together and execute.
"We just need to focus on doing on our job and not worry about anything else. And we're not," Yanda said. "The good thing is that everybody understands that if we all do our job at a high level, we'll be fine, just as it has always been. Keep our heads down and just freaking roll."
Baltimore Sun reporter Aaron Wilson contributed to this article.