Manly's injury-ravaged season came to an end on Sunday night as they fell 36-6 to the high-flying Panthers to finish the Telstra Premiership in 13th place.
It will be a year of 'what ifs' for the Sea Eagles after they went through the 24 rounds with the bulk of their salary cap sitting on the sidelines.
Sunday night typified their stuttering campaign with Nate Myles, Dylan Walker and Jorge Taufua all ruled out late with various ailments.
They started the match like a team getting ready for Mad Monday, down 30-0 at half-time to a Panthers side that was virtually faultless. They recovered to draw the second half 6-all, but by then the damage had already been done.
"The first half [where we conceded] 30 points wasn't good enough. We've got some work to do," Barrett said after the game.
"We obviously had some guys out there who are young and inexperienced but that's no excuse for the first half.
"The second half we came out and they did well and it could have gotten really ugly. We didn't have a hell of a lot to come out here and play for but we did have a lot of pride to play for.
"That would have been a horrific scoreline if they weren't having a crack.
"We just let ourselves down in the first half."
In what's been a year to forget for the rookie coach, Barrett has seen his troops floored by injury from as far back as the Auckland Nines in February.
Matt Parcell (14 matches), Jamie Buhrer (14), Brett Stewart (10), Brenton Lawrence (9) and Steve Matai (8) barely played half the season, while a number of other stars missed large chunks of 2016 through injury.
While the Sea Eagles have remained competitive for most of the year, Barrett said it was pointless trying to dissect their season given the mass changes to his final 17 every week.
"You can't take too much out of any of the games to be honest. We're going to have a rest now and we've got a lot of work to do next year," he said.
"In patches when we had the majority of our guys on the field, we strung some good games together.
"We just haven't been able to put the same side on the park, and I know it sounds like an excuse, but that's the reality of it. It's affected us big time. Hopefully the injury Gods smile on us a bit."
Sea Eagles back-rower Jamie Buhrer said one of the positives to come out of the constant chopping and changing to the squad was the emergence of several youngsters who he hopes will be stars of the future.
The development of the Trbojevic brothers, as well as the recent debuts of local juniors Brad Parker and Billy Bainbridge will only serve the club well, according to Buhrer.
"I've got a lot of confidence in the squad that we have," he said.
"As Baz touched on, injuries have been a fair part of our season and I suppose there are a lot of blokes that have been exposed to more minutes than they were ready for.
"It's probably a positive going into next year that they've gained that time and experience. It's only going to add to the depth of the team next year."