According to Darren Rovell of ESPN.com, an autographed Topps rookie card of Ohtani sold for $6,725 on Monday.
"His autographed cards have tripled or quadrupled in the last two to three weeks," said Rick Probstein, whose company was the one to sell the card on eBay, per Rovell.
The soaring market comes after Ohtani posted a 2.08 ERA, 0.46 WHIP and 18 strikeouts in his first 13 innings as an MLB pitcher and took a perfect game into the seventh inning of his last start, against the Oakland Athletics on Sunday.
That alone would be noteworthy, but he has served as a dangerous designated hitter on days he is not pitching, boasting a slash line of .389/.421/.889 with three home runs and seven RBI in 18 at-bats across four games.
If he continues his torrid pace, that $6,725 price tag will likely grow.