Russell Knox has officially withdrawn from the CJ Cup Byron Nelson. It's not uncommon for golfers to withdraw from a tournament even after the first round has technically begun. It teed off early on May 2, so some golfers have already scored. It is uncommon for someone to withdraw after being the replacement for another golfer, though.That's exactly what Knox did. He replaced Sean O'Hair just hours ago, but he is himself now out as well. In his place is Scott Piercy, who will hopefully play and not have to withdraw like his predecessors.It is unclear what drove Knox to withdraw. The PGA Tour communications page on X, formerly known as Twitter, announced that he was leaving and that Piercy was coming in. It did not reveal the cause, though injury or illness is possible. Who has good chances of winning the CJ Cup Byron Nelson?Only a few players have teed off already. As it stands, at about 9 am EST on May 2, Justin Lower is among three players tied for the lead. He is one under par after one hole. That's good enough to be tied with Alex Noren and Chun An Yu.Who will win the CJ Cup Byron Nelson?Since it's so early, most golfers haven't teed off. Noren, however, was already among the favorites to win, so this is a good start for him. Via CBS Sports, here were the top odds of winning:Jordan Spieth +1200Jason Day +1800Si Woo Kim +2200Sungjae Im +2500Alex Noren +2500Adam Scott +2500Tom Hoge +2800Min Woo Lee +2800Byeong Hun An +3000Stephan Jaeger +3000Jordan Spieth comes in as the favorite, but he is followed very closely by Jason Day and others. It should really be a good tournament, with a lot of top golfers competing for the ultimate prize. There is a $9.5 million prize purse, and the winner gets over $1 million for their performance at the CJ Cup Byron Nelson.