SAN DIEGO -- Just when it seemed the Colorado Rockies could take a deep breath, Nolan Arenado comes up with a bruised right hand that puts him in the day-to-day category entering the crucial final week of the season.

Nothing was said when Arenado departed in the middle of the sixth inning of the Rockies' 8-4 win over the Padres Sunday afternoon at Petco Park.

After the game, Rockies manager Bud Black said the third baseman's right hand "was swelling up during the game."

Losing the All-Star third baseman -- who leads the National League with 126 RBIs and is the game's premier defender at his position -- for any time this next week could be a severe blow to the playoff hopes of a Rockies team already in a bit of an offensive funk.

The Rockies entered Sunday's game having been shut out three times in a four-game span for the first time in franchise history.

Colorado did snap out of the funk Sunday, getting 12 hits, including back-to-back homers in the three-run ninth by Pat Valaika -- who entered the game as a pinch-hitter in the top of the sixth and stayed in to replace Arenado -- and Charlie Blackmon.

The win, coupled with losses by closest pursuers Milwaukee and St. Louis, gives the Rockies a two-game lead over the Brewers and a 2 1/2-game advantage on the Cardinals in the race for the final National League wild-card berth entering the final week of the regular season.

"It's big," Black said of Sunday's win. "These games are meaningful. Our guys are embracing it."

Colorado returns home from a 2-4 road trip to finish with six games at Coors Field against the Marlins and Dodgers -- while the Cardinals and Brewers play each other over the final weekend.

The Rockies are 43-32 at Coors Field this season.

"We're sharp at home," said Black. "We know how to play our park."

But they are not the same team without Arenado, who hit his 35th homer Friday night.

"I think I sprained the hand," said Arenado, who expects to miss only one game due to the bruising on the inside of his right palm. Arenado suffered the injury when he was jammed by a slider from Padres' starter Luis Perdomo in the third inning -- resulting on a soft line drive to Padres third baseman Christian Villanueva.

Arenado hit again in the fifth and grounded out. He also made a throw across the infield without incident.

The Rockies were speaking in optimistic terms regarding Arenado.

Meanwhile, right-handed starter German Marquez (11-7) held the Padres to two runs on five hits and three walks with three strikeouts over five innings to get the win. Right-handed closer Greg Holland, the last of six pitchers deployed by Black, struck out the side to get the final three outs in a non-save situation.

Valaika and Blackmon hit their one-out homers off Padres left-handed reliever Buddy Baumann to key the three-run ninth that broke open what had been a 5-4 game. Valaika earlier had doubled home Colorado's fifth run in the seventh as a pinch-hitter. Mark Reynolds also drove home two runs for the Rockies.

The Padres' first two runs came on a historic set of two-out, back-to-back home runs by Wil Myers and Yangervis Solarte in the first to erase a 1-0 Rockies lead.

Myers hit his career-high 29th homer on a 1-2 slider from Marquez that cleared the fence in center by about eight feet. Solarte followed by extending his career-high to 18 homers on a 369-foot drive to right off a fastball.

The homers were the 87th and 88th hit by the Padres at Petco Park this season -- the highest total ever for a home season. The Padres had 87 homers in both the 1992 and 1993 seasons at Petco Park.

Myers' homer was his fifth this month.

"I want to find a way to get better," said Myers. "I know it's there. I want to be more consistent."

The Rockies struck first in the top of the first on singles by three of the first four hitters who faced Padres starter and loser Luis Perdomo (8-11).

Blackmon opened the game with a single, moved to third on Arenado's one-out single back through the box and scored on Reynolds' single. The Rockies tied the game in the second without getting a hit. Ian Desmond walked, stole second, moved to third on a short wild pitch and scored when catcher Rocky Gale threw wildly to third after retrieving the errant pitch.

A second straight lead-off walk in the third led to Perdomo's downfall.

Blackmon moved to second on a single by DJ LeMahieu before Perdomo retired Arenado on a liner to third and Reynolds on a fly to right. But Gerardo Parra singled, scoring Blackmon and allowing LeMahieu to reach third. LeMahieu scored on Desmond's topped single up the third base line.

"The third inning was a ton of soft contact," said Padres manager Andy Green of the assault on Perdomo.

After Perdomo retired the last seven Rockies he faced, left-handed reliever Kyle McGrath retired the first two hitters he faced in the sixth before Trevor Story singled to right, stole second and scored when Valaika dropped a short double into center that ticked off the glove of the diving Manuel Margot.

At the time, that run was crucial.

Solarte opened the bottom of the sixth with a single and scored as September callup, third baseman Christian Villanueva, hit his third major league homer in a span of 17 major league at-bats to reduce the Rockies lead to 5-4.

NOTES: Each member of the Padres' six-man rotation is scheduled to make one more start with LHP Clayton Richard slated to make his final start Wednesday night at Dodger Stadium. But Richard has 192 1/3 innings and Padres manager Andy Green said Richard could pitch an inning or two on the final day of the season should he want to reach the 200-inning milestone for the first time since 2012. ... Rockies OF Carlos Gonzalez took Sunday off after landing hard on his left shoulder making a diving Saturday night. ... With 41 road wins this season, the Rockies tied the franchise record for road wins in a season. The only other season the Rockies finished with a winning road record was 2009.