Gross' seven walks and two wild pitches led directly to three of the five runs he allowed in six innings. Anthony Yacco was tagged for a solo home run by Tommy Whiteman and a three-run shot from Paul Lockhart in the seventh to finish the blowout.
The opener was picked up with two outs in the top of the seventh of a 3-3 tie after Friday's 1-hour, 49-minute rain delay.
Relievers Travis Anderson of Lexington and James Gregg of Hagerstown (27-30) mowed through the batting order on the restart.
Lexington (34-23) threatened in the 10th when Gavin Wright singled and Whiteman walked with two outs to chase Gregg. Ryan Meaux (2-1), Hagerstown's All-Star closer, came on to snuff the rally by coaxing Anthony Acevedo to fly out to end the inning.
Mike Gallo (1-2) squirmed out of two-on, one-out threat in the 10th, but couldn't match the feat in the 11th.
Mark Walker led off with an infield single to deep short, beating Whiteman's throw to first. After Justin Knoedler sacrificed Walker to second and Miguel Miranda struck out, Carter bounced a grounder up the middle through a pulled-in defense.
Center fielder Carlton Jimerson charged the ball and came up throwing. Walker tested his arm, slid into home and scored on a contested play at the plate for the Hagerstown win.
-- Before the game, the Suns sent struggling shortstop Leonel Cabrera to extended spring training camp in Arizona and replaced him with Tomas Garrido.
Cabrera, who has been struggling with a sore right wrist, was hitting .162 with five RBI. Garrido, who opened the season with the Suns last season, is being sent from Single-A San Jose.
Suns Today: vs. Lexington
Time: 1:30 Radio: WHAG 1410
Suns - Brian Burres (2-5, 6.19)
Legends - Manny Santillan (5-4, 1.54)