Marte, MLB.com's No. 40 prospect, is now 8-for-11 in five Grapefruit League games. The 22-year-old led the Double-A Eastern League with a .332 batting average in 129 games for Altoona last season.
Marte entered the game in the sixth, replacing Jose Tabata in the second spot in the Pirates order. After Jays right-hander Ryan Tepera walked Brandon Boggs on four pitches to open the seventh inning, Marte sent his fifth offering over the center-field wall for his first round-tripper of the spring campaign. He clubbed 12 homers for the Curve in 2011.
The right-handed-hitting Marte added a one-out single in the ninth. The Dominican native is 7-for-7 in his last three games after going 1-for-4 over the weekend.
Other Pirates prospects in the game did not fare as well. Pitcher Jeff Locke suffered the loss, allowing three runs on five hits over two frames. He struck out two and did not walk a batter.
Catcher Tony Sanchez, the Bucs' first-round pick in the 2009 Draft, made his second appearance of the spring, striking out to end the game.
For the Blue Jays, right-hander Drew Hutchison made his spring debut, allowing one run on two hits over two innings of relief. He was followed by Deck McGuire, who picked up the victory with a pair of scoreless frames. Both hurlers fanned one without issuing a walk.
Toronto improved to 3-2 in the Grapefruit League while Pittsburgh fell to 2-3. The Blue Jays host the Yankees in Dunedin on Thursday and the Pirates travel to Clearwater to take on the Phillies.