Another passenger, 24-year-old Jon Wilhite of Manhattan Beach, Calif., was in critical condition at UC Irvine Medical Center, The Associated Press reported. Wilhite played baseball from 2004-08 at Cal State Fullerton.
Stewart's mother said her daughter and Adenhart had known each other since last season but were not dating as far as she knew, according to The Associated Press.
All three of the deceased were in a Mitsubishi Eclipse, which police said was hit by the minivan.
A spokeswoman for the Angels said Adenhart and the other occupants of the Mitsubishi were headed for a country-themed dance club in Fullerton called In Cahoots.
According to Fullerton Police Lt. Kevin Hamilton, the accident occurred at about 12:23 a.m. Pacific Time when the van, which was eastbound on Orangethorpe Avenue, was believed to have run a red light at the intersection and broadsided the Mitsubishi, which was southbound on Lemon Street.
Hamilton said the impact spun both vehicles. One then hit a Honda driven by a 33-year-old man, who was northbound at the intersection, waiting to turn left.
The driver of the van, Andrew Thomas Gallo, 22, fled the scene, according to Fullerton Police Lt. Craig Brower. Gallo, of Riverside, Calif., was caught and charged with felony hit and run.
The passenger of the van, Raymond Alexander Rivera, 21, was taken to Western Medical Center-Anaheim with minor injuries, according to Fullerton officer Laura Markoski.
Police confirmed Gallo's license had been suspended prior to the accident for a previous drunken-driving conviction.
Adenhart is survived by his father, Jim, and mother, Janet.
His family released the following statement through the Angels organization:
"Nick's family expresses sincere gratitude for all the help the Angels have provided. He lived his dream and was blessed to be part of an organization comprised of such warm, caring, and compassionate people. The Angels were his extended family. Thanks to all of Nick's loyal supporters and fans throughout his career. He will always be in everyone's hearts forever."
The Angels postponed Thursday night's game at the request of Adenhart's family.
Manager Mike Scioscia said the team would get together, however.
In Wednesday night's game, Adenhart gave up seven hits over six scoreless innings. He struck out five and walked three before being relieved after the sixth inning with the Angels ahead 3-0. The Athletics won the game, 6-4.
Adenhart's father had flown from Baltimore to attend the game, AP reported.
Scott Boras, Adenhart's agent, said he spoke with the pitcher and his father, Jim, a retired Secret Service agent, in the clubhouse lobby until about 11:30 p.m. Adenhart and his father were staying at a nearby hotel.
Adenhart's mother, Janet, was flying to Anaheim on Thursday, according to AP.
The righthander was known nationally for his fastball while pitching for Williamsport High School. He was earmarked to be a top pick in the 2004 amateur draft, but hurt his elbow.
Los Angeles drafted Adenhart in the 14th round of the 2004 draft, even though he had just undergone reconstructive elbow surgery.
He made his Major League debut for the Los Angeles Angels on May 1, 2008, against the Oakland Athletics and pitched a perfect first inning.
-- Marlo Barnhart
o Orange County Register coverage of the fatal crash.