The Yankees fortifying their bullpen with Zach Britton has led to some casualties.

The Yankees dealt righty reliever Adam Warren to the Mariners on Monday, a day before the trade deadline, The Post’s Joel Sherman confirmed. The Yankees will be receiving international signing bonus money — which they have been hoarding — in return. Whether any players would be coming from Seattle was not immediately known.

Warren, in his second go-round with the Yankees, had a 2.70 ERA in 30 innings this year, though he had a tough month of July, allowing six runs in 10 innings.