Can anybody beat Stanford? At the start of the 2019 volleyball season, it's hard to imagine any team toppling the defending champions, overwhelming favorites to win their third NCAA title in four years.

The cast includes three first-team All-Americans in national player of the year Kathryn Plummer, setter Jenna Gray and libero Morgan Hentz. Coach Kevin Hambly snagged a key transfer to fill the void left by graduated middle blocker Tami Alade. Plus, Stanford, No. 1 in the AVCA's preseason poll, comes in touting the nation's highest-rated recruiting class.

But let the Golden State Warriors serve as a reminder that nothing is a given. As dominant as the Cardinal were a year ago, an underrated Nebraska team came within a few points of the upset in the national championship.

Expect No. 2 Nebraska to be a factor again in a loaded Big Ten with No. 3 Minnesota, No. 5 Wisconsin and No. 8 Penn State all worthy contenders.

Here's a primer to the season, which culminates at the final four in Pittsburgh in December.

Players to watch

Kathryn Plummer, 6-6 opposite hitter, Stanford: College volleyball's most decorated player returns for a final year after thrice being named an All-American first teamer and earning back-to-back espnW player of the year honors. The two-time AVCA player of the year became just the second in volleyball to win the AAU James E. Sullivan Award, given to the most outstanding amateur athlete in the United States. What's left to accomplish for the game's most decorated star? A third NCAA title would fit right in with the Californian's other hardware.

Dana Rettke, 6-8 middle blocker, Wisconsin: Expect the trajectory to keep climbing for the 6-foot-8 middle blocker, a two-time first-team All-American. Learning under Karch Kiraly as the youngest member of the 25-member U.S. national team should pay off for the tallest player ever to wear a Badgers uniform. The Big Ten leader in blocks packs a punch, too, as she is the nation's top returning hitter.

Jacqueline Quade, 6-2 outside hitter, Illinois: Adjusting to a new setter will be key for the first-team All-American outside hitter, a six-rotation player coming off a breakout season when the Illini pushed Nebraska to five sets in the national semifinals. Quade, among the best all-around players in volleyball's toughest conference, paced the Big Ten a year ago with 560 total kills. Don't be surprised to see the Indiana native elevate her game another notch.

Illinois outside hitter Jacqueline Quade led the Big Ten with 560 total kills and came within one set of leading the Illini to the national title game. Craig Pessman/Illinois Athletics

Sleepers

Kendall White, 5-5 libero, Penn State: The fiery libero and reigning Big Ten defensive player of the year ignites Penn State with an infectious spark.

Lauren Stivrins, 6-4, middle blocker, Nebraska: The junior middle blocker improved last year in every significant category and ranks just behind Rettke among returning hitters. She'll be a critical leader on this young Cornhuskers team that doesn't have any seniors.

Leah Edmond, 6-2 outside hitter, Kentucky: The 2018 SEC player of the year needs just 251 kills to become the program's all-time leader. Expect her to shine her senior year for the No. 7 Wildcats, hungry to make a postseason run and repeat as conference champions.

Contenders

Stanford: Remember a year ago when there was the feeling that anything short of a national title would be a disappointment to the Cardinal? Expect them to be dominant behind the stellar senior class of Plummer, Hentz and Gray, and a key transfer in 6-foot-3 graduate student Madeleine Gates, a second-team All-American middle blocker at UCLA last year. These seniors only know final four, and 2019 will likely continue that streak.

Nebraska: With no seniors, it's tempting to regard this as a rebuilding year. But Nebraska's been to four straight final fours and returns 10 players from last year's national runner-up squad, sophomore setter Nicklin Hames and outside hitters Lexi Sun and Jazz Sweet among them. Highly touted freshmen Madi Kubik (outside hitter) and Kenzie Knuckles (libero) joined the team in January and are expected to start. A 17-day Asian tour provided much-needed experience for a team that would surprise no one by peaking in postseason.

Wisconsin: The Badgers have all the pieces to return to the final four for the first time since 2013. Aside from Rettke, they boast the Big Ten's top returning setter, Sydney Hilley; consistent pin hitters in Madison Duello, Molly Haggerty and Grace Loberg; and an excellent passer in Tiffany Clark. Anything can happen in the Big Ten, but expect Wisconsin to make a run.

Dana Rettke was the youngest member of the U.S. national team. Can the 6-foot-8 middle blocker help the Badgers reach their first final four since 2013? Tom Lynn/Wisconsin Athletic Communications

Dark horses

Penn State: A 14th final four would feel like a home game for Nittany Lions fans, who could easily trek to PPG Arena in Pittsburgh, just a 2½-hour drive from University Park. Penn State will be fueled by White, the first Nittany Lion libero to earn first-team All-American honors. Jonni Parker, the Big Ten freshman of the year, leads a special sophomore class that advanced to the final eight last postseason.

Kentucky: Edmond, setter Madison Lilley, defensive cog Gabby Curry and SEC freshman of the year Alli Stumler pushed this team to the regional semifinals last year, when Nebraska ended the run. That core returns, and the Wildcats added graduate transfer Leah Meyer, a middle blocker from Duke. Creighton, Utah and USC will provide early tests.

USC: Brent Crouch returns for his second season as head of a Trojans team that returns its engine in outside hitters Khalia Lanier and Brooke Botkin, as well as setter Raquel Lázaro, the Pac-12 freshman of the year. Graduate student Abril Bustamente, who won two NCAA titles on USC's beach team, will transition into a defensive role. Expect big things from freshman Madison Horin. With Lanier and Botkin healthy after concussions limited both last season, it's no surprise USC is picked to finish second to Stanford in a top-heavy conference.

Games to watch

No. 4 Texas vs. No. 9 BYU, Sept. 13 in Wichita, Kansas: The Cougars swept the Longhorns with the final four at stake last year. This time, let's see how Texas fares on a neutral floor behind preseason Big 12 player of the year Micaya White and 6-foot-2 outside hitter Skylar Fields, the top recruit in the freshman class.

No. 11 Oregon vs. No. 3 Minnesota, Sept. 13 at University Park: It's a rematch of last year's regional semifinal when the Ducks stunned Minnesota 3-1. (Remember that 41-39 second set?) The result denied the Gophers the chance to advance to a final four in their hometown. Oregon also defeated Minnesota 3-1 in a regular-season game last year.

No. 1 Stanford at No. 2 Nebraska, Sept. 18: Yep, it's a rematch of last year's exhilarating national championship, which the Cardinal gutted out 15-12 in the fifth. In fact, these teams combined for every NCAA title since 2015. Even though the Huskers graduated dynamo Mikaela Foecke, here's what's clear: A raucous standing-room crowd will be stoked to see the Big Red vs. Cardinal red at Devaney, where Nebraska's sellout streak dates back to 2001.

Watch NCAA volleyball games on the ESPN networks and the ESPN App all season long.

More storylines

Three Oregon transfers and five freshman give Hawaii a whole new look under third-year coach Robyn Ah Mow. An opening weekend tournament that includes games against Washington and San Diego will be early barometers for a Rainbow Wahine team eager to reclaim its dominance in the Big West.

While BYU will miss Roni Jones-Perry and Lyndie Haddock-Eppich, the Cougars welcome back national freshman of the year Heather Gneiting, Mary Lake, a second-team All-American, and Kennedy Eschenberg, an honorable mention All-American. All received significant international experience during the offseason. Don't underestimate BYU, led by national coach of the year Heather Olmstead. Entering her fifth season, she boasts an 118-13 mark.

Keep an eye on Jordan Thompson, a senior at Cincinnati, who led the nation in points and had 240 more kills than the player behind her. Her summer included helping Team USA to an Olympic berth, experience she'll use to help her Bearcats earn a return trip to the national tournament.