On the day 1,000 fans returned to Montgomery Waters Meadow, Town fell to their first League One reverse of the season after a second-half error from loan goalkeeper Matija Sarkic saw Sam Hoskins score to hand the newly-promoted Cobblers all three points.
Shaun Whalley's goal earned Town a deserved equaliser after Northampton had taken a 12th minute lead through Mark Marshall - as the hosts struggled to find their feet after influential defender Ebanks-Landell was an early injury victim to a head knock he picked up inside 30 seconds.
From Northampton's opener onwards Town were dominant and looked the side most likely to push for a winner before Sarkic's error.
Ricketts said: "It's hugely frustrating losing the game. We've had 70 per cent possession, 19 shots.
"One of the biggest disappointments today was losing Ethan after 10 seconds which was a big blow.
"We were missing other players today so to lose Ethan was a blow.
"We couldn't reset after losing our captain. Their goal was disappointing from my point of view. Hugely frustrating.
"Large parts of the game were very good. We scored one but we should've scored more. From 19 shots only five were on target.
"We need to do more from the situations we got into, which should've led to more goals."
Ricketts confirmed Ebanks-Landell, who had the captain's armband in the absence of the suspended Aaron Pierre and Ollie Norburn - who was missing after the tragic passing of his son Louie - had not sustained concussion.
On Whalley's well-taken equaliser after a superb pass from the lively Jason Cummings, the boss added: "It was about time. On top of 19 shots we've had unbelievable positions where we should've scored more goals.
"There was an awful lot of good today but we've given two really poor goals away and that's what's cost us."
Sarkic's error comes off the back of a superb debut at Portsmouth last week and is the second game from three this season where keeper mishaps have cost Shrewsbury, after the Carabao Cup exit at Middlesbrough.
"We got caught on the break," Ricketts said of the winner. "We were in possession and in control. We should probably stop the action before it.
"Mati is a great young keeper, he's made a mistake. It was the right decision to control the situation, maybe just side-foot the ball there to control it and make sure it doesn't go anywhere.
"It was a freak thing which went against us today and not for us."
Town, one of seven EFL pilot schemes for the safe return of fans, can hold their heads high after the fixture passed without incident with 1,000 supporters safely socially-distanced in the West Stand.
"It was excellent, I was really pleased and delighted for everyone at the club we were chosen as a pilot," Ricketts added.
"I'm bitterly disappointed we haven't sent them home happy with three points but I think you could see from their reaction at the end of the game they could see the huge strides we've taken and the quality in our game.
"We're disappointed at not winning it but there were so many positives to take out of it and I'm hopeful they saw those and will pass on the word of what we're trying to do.
"We're all in football because we love it but everyone wants to perform in front of people. It helps certain players and gets more out of them.
"As players and staff we'd always rather play in front of crowds and entertain the people here."