The 35-year-old leaves with more than 10,000 first-class runs and 25 centuries to his name from 143 matches over 14 years.

"I feel proud, I felt like I eked every inch of output out of what I had and never left anything in the tank," Cowan, said.

He averaged 34.70 this season without a century and scored just 11 runs in total as NSW dropped out of Shield title contention with this week's loss to Victoria.

Cowan felt he was still playing well and contributing for NSW "but they weren't match-winning contributions".

"Often times gone by that killer instinct of turning a nice 60 into a 150 and winning the game, I really prided myself on," Cowan said.

"I was getting out for 60 or 70 and not really minding if someone else had to do it and, those kind of moments, I thought this is not fair for the rest of the guys in the team.

"NSW cricket have a duty to provide the vast majority of Test players and if that's my attitude then we should be getting the next Steve Smith in and finding who that is and giving them a game, so Australian cricket can maintain the rage."

Cowan was awarded the Steve Waugh Medal as NSW's best player last summer after topping the Shield run-scoring chart with 959 at an average of 74.

He missed out to Daniel Hughes for a spot in a full-strength NSW batting line-up at the start of the season.

Cowan played 18 Test from 2011-13, averaging 31, with a high score of 136 against South Africa in Brisbane his only century.

"Could I have played more Test cricket? If the game pans out a different way and you get a call here or there, there are such small margins in the game right through," he said.

"I don't really reflect like that. I feel very lucky to have played Test cricket and to be given the opportunity."

The dogged left-hander made his start in NSW but his career flourished after he moved to Tasmania, before he returned to Sydney to finish his domestic career with his home state.

"I'd dreamed growing up playing for NSW just as much as playing for Australia I feel incredibly lucky to finish my career here," he said.

"Having said that I loved my time in Tasmania because that's a time of my life I look back with only happy memories, great team, great people that turned a fringe state cricketer into a Test opening batsman."

Australian Associated Press