FRISCO, Texas -- Plane rides after a loss can seem interminable.

Defensive coordinator Mike Nolan sat down after the Dallas Cowboys' 38-31 loss to the Seattle Seahawks almost dreading what he was about to watch on the ride home Sunday night.

"I would say it's just disappointing to lose and in particular when you give up big plays, that always kind of hurts you even more," Nolan said. "The most disappointing thing was at the end of the game when we had them in a situation where we could have won the game, or at least get pretty close to it had we stopped them on the fourth down, that was a big play in the ballgame, for us anyhow. So there's little battles here and there that disappoint more than others."

Through three games, the Cowboys have given up 97 points, the most in franchise history. Leaguewide, only the Minnesota Vikings and Atlanta Falcons have given up more. The Cowboys are giving up 404.7 yards per game with only six teams giving up more.

That there are growing pains is not a surprise, considering the circumstances created by the coronavirus pandemic. The plan was installed virtually instead of face to face. There was no offseason program complete with organized team activities and a minicamp. Training camp was shortened. There were no preseason games.

While every team has dealt with the same circumstances, those with new coordinators have a similar story. There are 11 teams with new coordinators, if not new schemes, and eight rank in the bottom half of the league in yards per game and nine are in the bottom half in points per game.

"It's more than one thing," Cowboys coach Mike McCarthy said. "It always is. Always will be."

Here are some factors contributing to the slow start by the Cowboys' defense.

Faced good quarterbacks

Nobody has thrown more touchdown passes through three games in NFL history than Seattle's Russell Wilson (14). Atlanta's Matt Ryan might have an 0-3 record but he is still a quality quarterback. Jared Goff (Los Angeles Rams) has the seventh-best QBR through three games (76.4).

Aside from Aldon Smith, who leads the NFL in sacks with four, Dallas' pass rush has not been good enough. The secondary has been troubled by injuries and missed on at least three opportunities for interceptions.

This week, the Cowboys face Baker Mayfield and the Cleveland Browns (1 p.m. ET, Fox). The Browns' quarterback has a plethora of weapons and the third-best rushing offense in the NFL.

The Cowboys have plenty of good-to-great quarterbacks on the upcoming schedule, including Arizona's Kyler Murray, Philadelphia's Carson Wentz, Pittsburgh's Ben Roethlisberger, Minnesota's Kirk Cousins and Baltimore's Lamar Jackson.

Big plays

On the Seahawks' sixth play, running back Chris Carson had a 23-yard run. On the seventh play, receiver Tyler Lockett had a 43-yard touchdown catch. On the 13th play, receiver DK Metcalf had a 62-yard catch that should have been a 63-yard touchdown if not for a hustle play by Cowboys cornerback Trevon Diggs.

On the Seahawks' final drive, the Cowboys gave up a 21-yard completion to tight end Greg Olsen and the winning score, a 29-yard Wilson pass to Metcalf.

"People aren't supposed to run that wide open," McCarthy said when asked if teams are taking advantage of the safeties.

The Cowboys have given up 15 plays of 20 yards or more, tied for third most in the league through three games.

The premise of the Rod Marinelli/Kris Richard defense last season was to make offenses execute long drives. In the first three games last season, the Cowboys gave up nine plays of 20 yards or more, although they did not face quality quarterbacks. In the final eight games of the season, they gave up at least four plays of 20 yards or more seven times.

This appears to be an issue that pre-dates Nolan.

Injuries

Defensive tackle Gerald McCoy was the Cowboys' biggest free-agent signing. He suffered a torn quadriceps in the first padded practice of training camp. Linebacker Sean Lee has not practiced at all and is rehabbing from sports hernia surgery that will keep him out a few more games.

In the first quarter of the first game, starting middle linebacker Leighton Vander Esch suffered a broken collarbone and is on injured reserve, expected to miss at least another month. Starting cornerback Anthony Brown was lost before Week 2 because of broken ribs suffered in practice, and the other starting cornerback, Chidobe Awuzie, suffered a hamstring strain. They are both on injured reserve.

"That will always be your biggest challenge just because the 'next man up' is a nice thing to live by, but there is a reason that somebody's a starter and somebody's a backup," Nolan said. "And maybe one day that backup would become the starter, but I would rather work on the eventual thing than the right now. And sometime the injuries force a young guy to step up and do it, and that's just everybody lives in that environment in the NFL."

Their 'stars' have not played like stars

The Cowboys' best defender in the first three games has been Aldon Smith, and he had not played since 2015. Their second best defender so far might be linebacker Joe Thomas, who took over for Vander Esch.

If you're in a "next man up," world, then your highest-paid players have to lift those around them by playing better.

That has not happened yet.

Defensive lineman DeMarcus Lawrence, who was guaranteed $65 million as part of a five-year, $105 million contract last year, has played more than 400 snaps since his last full sack, which came in the first quarter of last season's Week 8 win against the New York Giants. His last half-sack came on Thanksgiving against Buffalo.

Lawrence has been slowed lately by a knee injury, but he has not had a quarterback hurry or a pass deflection in two games.

Linebacker Jaylon Smith, who was guaranteed $35.5 million as part of a $64 million deal signed last year, has one tackle for loss. He was exposed in coverage in the loss to the Rams and he could not run with Wilson last week.