Triple-A Reno's first baseman hit two home runs and accumulated seven RBIs in the Aces' 10-8 loss to Fresno on Thursday night.
The 34-year-old slugger stroked a grand slam off Grizzlies starter Yusmeiro Petit in the fifth inning and added another three-run blast in the top of the ninth.
Ruiz, who has seen time in the Majors with the Blue Jays and Twins, spent parts of two seasons with the Tohoku Rakuten Golden Eagles of Japan's Pacific League. He mustered only a .195 batting average in 38 games for the Golden Eagles in 2011.
After signing a Minor League deal with the D-backs, Ruiz was assigned to Reno, returning to the PCL for the first time in three years. In 2009, the native of the Bronx, N.Y., tore apart the PCL, hitting .320 with 25 home runs and 116 RBIs in 114 games for Toronto affiliate Las Vegas. That year, he was named a PCL All-Star and the circuit's Most Valuable Player.
He is hitting .321 with three home runs and 13 RBIs through 14 games this season. His RBI total, 10 of which have come in Ruiz's last two games, ranks seventh in the PCL thus far.
Fresno provided its own firepower with an eight-run seventh inning. The home team sent 12 batters to the plate and recorded nine of its 10 total hits in the inning.
Left fielder Roger Kieschnick led off with a single and later doubled in the same frame, becoming the first Fresno player to collect two hits in an inning since Edgar Gonzalez on Aug. 12, 2011. Kieschnick was the only member of his team to have a multi-hit day despite the offensive outburst.
Reno reliever Bryan Woodall (0-1) suffered the bulk of the damage in the frame, surrendering three earned runs on three hits in one-third of an inning.