That makes four players who have tested positive in the last 12 days. The Barbasol Championship was the first tournament since the Valspar Championship in late April that had more than player receive a positive COVID-19 test.
The Barbasol Championship is held opposite the British Open. Purdy, whose lone PGA Tour victory was in 2005 at the Byron Nelson Championship, started out as the sixth alternate when the field was set last Friday. Couch's only PGA Tour title was in New Orleans a year later. He was listed as the third alternate.
They were replaced by Eric Axley and Smylie Kaufman on Tuesday.
Zach Johnson had a positive COVID-19 test after the John Deere Classic and had to withdraw from the British Open.
Hideki Matsuyama received a positive test after the first round of the Rocket Mortgage Classic. Even though he is asymptomatic and completed his 10 days of isolation, Matsuyama kept testing positive and had to withdraw from the British Open.
In a June 28 memo to players, the tour said testing as a condition for competition would end starting with the 3M Open in Minnesota next week.
Players who have been vaccinated do not need to be tested.
Purdy has played three times this year, two opposite-field events and the one-time tournament at Congaree in South Carolina. Couch has only played the Puerto Rico Open this year, an opposite-field event, and missed the cut.