Briley's season totals heading into this weekend's district title contest include 221 kills, a .251 hitting percentage, 392 assists, 146 digs, 35 blocks and a team-high 45 service aces.
"I'm very excited to play at Rio Grande next year,"she said. "I've wanted to play college ball since I was in middle school."
Briley, a four-year member of the varsity team at Pleasant, was named her team's most improved player in 2010 and earned Central District Player of the Year honors last season.
The Spartans have won 11 straight sectional championships. After a 6-4 start to the 2012 campaign, PHS has won 13 of its last 14 outings en route to its sixth district championship game appearance under Atherton.
"Having a setter with Kayla's size and leaping ability, we'll have more options as an offense," Donaldson said. "She can play front row as a setter because of her size and vertical."
Briley, who plans to major in Nursing, elected to sign with the RedStorm after also receiving interest from Heidelburg University.
"I chose the University of Rio Grande because I really like coach Donaldson as a person and I felt like Rio was the best fit for me," she said.
"I feel like I can bring the knowledge of the game with me and I hope to improve on my vocal leadership skills," Briley added. "My ultimate goal over the next four years is to become the best volleyball player I can be."
Donaldson thinks the addition of Briley will pay instant dividends for the RedStorm.
"She is a force as a blocker, as a hitter and as a setter," Donaldson said. "Kayla will change the dynamics of our team the moment she steps onto the court. She's a well-rounded, well-trained player who will make an impact in the seasons to come."
Donaldson also signed fellow Pleasant High senior Autumn Snider on the same trip to the school.
"These two girls are great players and play well together. They have the mentality that I've been looking for in players since I started at Rio," she said. "I've had the pleasure of coaching some very fine players who were great individuals as well. I'm looking forward to their careers."
Briley is the daughter of Greg and Kristy Briley of Marion.