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 Portland State linebacker AJ Schlatter died at the age of 20 on Sunday at approximately 9:15 p.m. PT because of an apparent blood clot. 
 
 Schlatter's father posted on Facebook about his son's death Monday, explaining the blood clot may have occurred following surgery to remove his tonsils, which he underwent Friday: 
 
 Per the Vikings' official website, Schlatter appeared in 11 games and started 10 this past season, racking up 62 tackles (6.5 for loss), two fumble recoveries, two sacks and an interception. 
 
 The Oregonian's Ken Goe passed along statements from Vikings head coach Bruce Barnum and athletic director Mark Rountree. 
 
 "My heart is with the Schlatter family. They are our focus right now," said Barnum. "We lost a diamond that will never be replaced. He was the definition of what we are about at PSU." 
 
 Rountree offered condolences to the Schlatter family in his remarks: 
 
 Our thoughts and prayers go out to the Schlatter family with all the compassion and sympathy we can bring to bear during this difficult time. Things like this aren't supposed to happen. We cherish every student's well-being, and the loss of AJ will be tough on our family. He represented his family and Portland State with passion, courage, and humility that made us all proud. He will be missed. 
 
 Per Goe, Schlatter's father was an assistant football coach for the Vikings in the 1980s. His mother, Terri Jo, played volleyball at Portland State, as did his sister, Garyn. 
 
 After redshirting during the 2014 campaign, Schlatter burst onto the scene for an exceptional Portland State team that clinched a berth in the FCS playoffs with a 9-3 record. ||||| Portland State is mourning the sudden loss of linebacker AJ Schlatter, who died Sunday at home due to a complication from minor throat surgery. 
 
 The 20-year-old Schlatter's father Jim wrote a Facebook post Monday saying he believed his son developed a blood clot after having his tonsils removed Friday. 
 
 "He was such a inspiration to me and I was and am so PROUD to be his father," Jim Schlatter wrote. 
 
 Schlatter, a native of Canby, Oregon, was a redshirt freshman and starter for a Vikings squad that finished the season ranked No. 10 in the nation after making the FCS playoffs for the second time. 
 
 "My heart is with the Schlatter family. They are our focus right now," coach Bruce Barnum said. "We lost a diamond that will never be replaced. He was the definition of what we are about at PSU." 
 
 Originally a walk-on, Schlatter earned a full scholarship with the program through hard work. As a freshman, he had 62 tackles and was named the Big Sky Defensive Player of the Week following a win over Eastern Washington on Nov. 21. 
 
 Schlatter came from a family that has been ingrained in Portland State athletics. His mother, Terri Jo, played on the school's national championship volleyball team in 1984, became an assistant coach with the program and is a member of the school's athletics hall of fame. His father spent time in the 1980s as an assistant football coach, and his sister Garyn was a star volleyball player. 
 
 "Our thoughts and prayers go out to the Schlatter family with all the compassion and sympathy we can bring to bear during this difficult time," athletic director Mark Rountree said. "Things like this aren't supposed to happen. We cherish every student's well-being, and the loss of AJ will be tough on our family. He represented his family and Portland State with passion, courage and humility that made us all proud. He will be missed." 
 
 Funeral arrangements were pending.
– A freshman football player at Portland State died Sunday evening after having minor surgery—and his father says he's blaming himself. AJ Schlatter, 20, apparently suffered a blood clot after his tonsils were removed. "I failed my son tonight," his father, James Schlatter, writes on Facebook, per Bleacher Report. "I could not [resuscitate] him nor did the best efforts by ems and the emergency room staff. AJ Schlatter passed away approximately 9:15 Sunday evening." Little else is known, but Schlatter's father also expressed pride in the linebacker who went from walk-on to full scholarship with his widely hailed work ethic, ESPN reports. "In his 20+ years he became a greater man then I could ever dream of becoming," James Schlatter writes. AJ proved himself on the field, making 62 tackles and earning Big Sky Defensive Player of the Week honors after the Vikings beat Eastern Washington in November. He was also an "incredible leader" who "busted his rear end, day after day," and was "always humble, nice, classy, appreciative," a PSU social studies teacher tells the Portland Tribune. Other tributes are coming in from officials at the school, where James Schlatter was an assistant football coach and AJ's mother, Terri Jo, is in the athletics hall of fame for her time with the volleyball team. "Things like this aren't supposed to happen," says PSU athletic director Mark Rountree. "[AJ] will be missed." (A tonsillectomy-gone-wrong features prominently in the high-profile case of Jahi McMath.)