Especially on Twitter.
"I've had people say they hope me and my mom get AIDS and die," Mathews told Kevin Acee of U-T San Diego on Wednesday.
Vitriolic tweets are a new and unwelcome phenomena for the modern athlete, but Mathews would catch heat for his play in any era.
To be fair, he marched into a tough scenario in San Diego. Drafted 12th overall in 2010, Mathews was touted as the heir apparent to LaDainian Tomlinson, but durability and fumbling issues have shrunk those expectations.
"So far, what I've done right now, I've been just an average back," Mathews said. "I got a lot of people just frustrated with my performance in the last few years. They expected me to come in and do big things. And I expect myself to."
Mathews sports a solid 4.4 yards per carry average over 32 starts, but he hasn't been able to stay healthy enough to cement himself as an unquestioned starter. His three seasons have included a nasty sprained ankle and a twice-broken collarbone.
Still, general manager Tom Telesco said last month that he expects "big things" from Mathews, whom he labeled a "bellcow" back. Former Chargers coach Norv Turner lost patience with Mathews, but an offseason regime change has furnished the runner with another chance -- probably his last in San Diego.
Follow Marc Sessler on Twitter @MarcSesslerNFL.