Tracking down the San Diego Padres for fourth place in the NL West is unlikely for the Colorado Rockies, but they probably won't have to continue trying without a key slugger after an injury scare.

Nolan Arenado was removed from the series opener with a chest contusion, though the third baseman is confident he'll be back in the lineup for Tuesday night's follow-up at Petco Park.

After Colorado's 3-2 win Monday, the teams have six games remaining and San Diego (65-73) holds a 7 1/2-game advantage with nine wins in 13 meetings this season. It was the Rockies' second win in 10 tries at Petco, and it nearly came at a cost.

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Arenado, who is tied with teammate Carlos Gonzalez with an NL-leading 36 home runs, was removed in the eighth inning after landing in the crowd when trying to make a play on a foul ball.

"I will be OK," he said. "I got an X-ray and everything looked good. I expect to be in the lineup tomorrow."

Gonzalez and Arenado are each one home run shy of matching Jeromy Burnitz's 2004 total for the highest since the Coors Field humidor was installed in 2002. Prior to that, at least one Colorado player hit 40 or more home runs in six of the club's first nine seasons.

In addition to climbing a game closer to San Diego, Colorado (57-80) can get a step closer to its first series win against a division opponent since taking two of three at home from Arizona from June 23-25. The Rockies haven't won a road series in the West since sweeping San Francisco in three April 13-15.

Jon Gray is six starts into his career and still seeking his first decision. Gray (0-0, 6.15 ERA) was impressive through his first three with a 2.40 ERA, but he's since posted an 11.12 mark with a .472 opponent batting average while lasting 11 1-3 innings.

He gave up four runs and a season-high 10 hits in 5 1-3 innings of Wednesday's 9-4 home win over Arizona, though he's still taking positives.

"It's been three weeks of straight battling," Gray told MLB's official website. "I think it's easier every time to deal with that, so I think mental toughness is really what you're getting out of those type of games."

The right-hander will at least get a break from Coors Field, where he's posted a 7.88 ERA and .391 OBA in four starts as opposed to 3.48 and .211 marks in two on the road. His one respectable home start came in a 7-5 loss to San Diego on Aug. 15 while allowing a run and four hits in five innings.

Similar numbers against fellow rookie Colin Rea (2-2, 5.47) could finally get him in the win column. Rea won his first two starts and is 0-2 in three since, but his numbers have stayed more level than Gray's.

The right-hander is yet to make it through six innings, but he was removed after giving up two runs in five of Thursday's 10-7 home win over Los Angeles because he took a liner off his pitching shoulder.

"I thought he was very poised for a start against the Dodgers," interim manager Pat Murphy said. "I think he showed me something. In all his outings this was his best one in my opinion."

Getting Rea another win could require a return to that level of offense. Since that game, the Padres have lost four straight with nine runs and a .190 average.

Matt Kemp has driven in four of those runs and has 31 RBIs in his last 22 games.