If you use a long line - you must have him on a harness - so he doesn't break his neck when you tread on the line
That's how I trained my English Setter when her recall started to do settery things - harness, long line - whistle, and clicker, and treats - blow whistle, reel dog in, click and treat as she got to me. Every day for three weeks - then we had a whistle recall that worked 95 times out of 100.