Disappointed Sadler accepts Northants didn't perform well enough to avoid the drop
The County's relegation to division two was confirmed on Friday when they played out a draw with title-chasing Surrey at the Kia Oval.
A win would have taken the club's survival bid to the final match of the season against Essex this week.
But despite dominating the leaders over four days and even enforcing a follow on, the home side got their act together to bat out the final day without losing a wicket in their second innings to earn a share of the spoils.
That left Northants 25 points adrift of safety with only one game to play and means they return to the second tier for the first time since winning promotion in 2019, although due to Covid they have only played two full top flight seasons.
It has been a poor campaign in all formats for the County, who also failed to reach the knockout stages of both the Vitality Blast and Metro Bank One Day Cup.
The bowlers can take credit for doing their job for most of the summer in the four-day game, but it has been with the bat where the County's major problems have been.
In the Championship, Northants have won just one of their 13 games - against Middlesex in mid-April - and collected a paltry seven batting bonus points all season.
Northants, who have lost eight of those 13 encounters, have only passed 350 once in the first innings of a match - at the Oval last week - and on three occasions in April and May they were dismissed for double figure scores (56, 63 and 72).
“We are of course very disappointed to be relegated," said Sadler.
"We had high hopes at the start of the season but we simply did not play good enough cricket in the first half of the summer."
A source of frustration for Sadler will have been the team's improved performance in the past two games, playing well and being edged out by two wickets at Warwickshire last week, and then getting the better of the champions-elect in a rain-affected match in south London.
Northants made their highest first innings total of the season in making 357 all out, with Indian overseas signing Karun Nair hitting a brilliant 150, and then bowled out Surrey for just 185.
But former England men Rory Burns and Dom Sibley then made 71 not out and 67 not out respectively as Surrey battled to 142 without loss in their second knock.
“Although it’s frustrating not to have played the way we can – and this week showed just what we are capable of – I am immensely proud that we dominated the best team in the country in this match," said Sadler.
"We showed this week how good we can be.
“Karun Nair played one of the best innings I have seen for a long time and, as a team, we batted really well throughout our first innings on a green pitch, under the floodlights for virtually all of the time and against a Test-class attack.
“Then our seamers really ran in and put Surrey under pressure in their first innings, for session after session.
"We spoke about trying to finish off their first innings quickly on the final day and then trying to take early wickets to put them under pressure again when they followed on.
"We did the first part but we then couldn’t get those early wickets despite a couple of close lbw decisions and an edge that dropped just in front of the slips, and in the end there just wasn’t enough time left in the game.”
Although they are relegated, Northants are still going to have a big say in the destination of the County Championship title in the final round of games.
They host second-placed Essex at the County Ground on Tuesday, and the Chelmsford side go into that game 20 points adrift of Surrey, who travel to third-placed Hampshire in their final fixture.
The match should see former Northants skipper Adam Rossington return to Wantage Road for the first time since his surprise departure at the start of the 2022 season.