Knowles, a junior at St. Francis High, will participate in the 300-meter intermediate hurdles at 7:45 p.m. He'll be an alternate in the 110 high hurdles, which will begin at 6:47.
Kostelnik, a senior at Loyola and a Glendale resident, will team with Morgan Simon, Elias Gedyon and Lee Hightower in the 4x400 relay at 8:50. The UCLA-bound Kostelnik is an alternate in the 800, which will start at 7:29.
Athletes who secure a top-five finish in their respective races automatically qualify for state. Those who fall out of the top five, however, can still march on to state by securing at-large berths if they meet predetermined qualifying marks for their specific event.
The automatic qualifying times in the 110- and 300 hurdles are 14.41 and 38.26 seconds, respectively. The qualifying mark in the 800 is 1 minutes 54.23 seconds and 3:18.48 in the 4x400 relay.
The 93rd annual CIF State Track and Field Championships will take place June 3-4 at Buchanan High in Clovis.
Knowles, who placed ninth overall in the 300 hurdles (38.38) and 10th in the 110 (14.62) during the division finals Saturday at Cerritos College, said he's put in additional time at recent practices to help round him into form.
"All of my workouts have been hard throughout the season," said Knowles, who won league championships in both events May 5 at L.A. Valley College. "It's all mental from here.
"I can start off a little harder and finish the race hard. My technique has progressed a lot lately. I have pretty good form and haven't been stuttering. I'm very happy and proud that I'll be representing St. Francis."
St. Francis Coach Pat Donovan said Knowles picked up some valuable experience at the division finals and will look to carry that over against some of the top competitors from around Southern California.