It is understood that Koiki is also attracting interest from Rangers ahead of the 2022/23 campaign.
Derby are currently on the lookout for a new left-back following Lee Buchanan’s departure and thus Koiki could potentially fit the bill.
Buchanan opted to seal a move to Werder Bremen earlier this month.
Koiki emerged as a key player for the Cobblers during the 2021/22 campaign as they secured a fourth-place finish in the League Two standings.
The left-back made 49 appearances for the club in all competitions and scored his only goal during the first leg of Northampton’s play-off semi-final with Mansfield Town.
Eliminated from this competition by the Stags, the Cobblers are set to feature in the fourth-tier again next season.
Derby will need to pay a fee for Koiki as Northampton opted to trigger an option in his contract earlier this year that will see him remain at Sixfields until 2023.
The Rams have already signed a plethora of players this summer as they prepare for life in League One.
Kwaku Odoroh became the latest individual to seal a move to Pride Park yesterday as he signed a two-year deal.
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If this report turns out to be true, it will be interesting to see whether Derby are able to win the race for Koiki’s signature in the coming weeks.
By providing the defender with assurances regarding game-time, the Rams could potentially fend off competition from Rangers.
Having averaged a respectable WhoScored match rating of 6.84 in League Two last season, Koiki will be confident in his ability to deliver the goods on a consistent basis in a higher division.
When you consider that Koiki has previously played for Bristol Rovers in League One, there is a chance that he could hit the ground running at Derby if they convince him to make the switch to Pride Park.