Saints boss Chris Boyd says Heinrich Brüssow's desire to avoid letting people down was a key reason why the South Africa flanker decided to retire.
And Boyd was quick to pay tribute to Brüssow for the work the 33-year-old has done both on and off the pitch at Franklin's Gardens.
Brüssow has only been able to make 21 appearances for Saints since joining the club from Japanese Top League side NTT Docomo Red Hurricanes in January 2018.
But he has been crucial in the development of players such as Teimana Harrison and Lewis Ludlam, who is currently at the World Cup with England.
“Heinrich is a great rugby player, a great man and was a complete professional on and off the field," Boyd said.
"He played in an era of great openside flankers, and at his best he was at the very top of the class.
“The young loose forwards at Saints, especially Lewis Ludlam, have benefited greatly from him passing on his considerable knowledge to them.
“Heinrich has been to the top of the high-performance mountain and seen the view – unfortunately a succession of injuries have prevented him physically from climbing that mountain any longer.
“The frustration of not being able to consistently perform for himself and for Saints has prompted him to retire, but the decision not to let others down is a true mark of the man.
"He wants to be able to play at 100 per cent, or not at all.
“We all thank Heinz for his contrubtion to Northampton Saints, and wish him and his family all the best for their future.”