If the San Francisco Giants or Colorado Rockies are going reach the postseason, they're going to need some help to get there.

But first, they'll have to win as many games as they can, including the one they one another in San Francisco on Wednesday.

As for the help from others, the Philadelphia Phillies are among those cooperating, taking four consecutive losses. As for themselves, the Giants have the upper hand after a 5-2 win over the Rockies on Tuesday.

San Francisco jumped over the Phillies and into a tie with the Cincinnati Reds and the Milwaukee Brewers for the two NL wild cards while the Rockies fell three games back. San Francisco and Colorado each have six games remaining, with all of the Rockies' remaining contests on the road.

The Rockies (24-30) will send rookie right-hander Ryan Castellani to the mound in the third game of the four-game series on Wednesday. The Giants (27-27) had not announced a starter as of Tuesday night.

Castellani (1-3, 5.59 ERA) made an impressive major league debut, but in his past five games, four of them starts, he is 0-2 with a 7.85 ERA. The only relief appearance he made in that stretch came against the Giants on Sept. 2, when he pitched two scoreless innings in a come-from-behind win for the Rockies. It was his only action against San Francisco thus far.

Colorado has received solid starting pitching over the past three games, which is even more important since perennial Gold Glove third baseman Nolan Arenado went on the 10-day injured list Monday due to inflammation in his left AC joint. The job of filling his shoes has fallen to the versatile Ryan McMahon, who has played every infield position this year.

McMahon feels most comfortable at third, where he has been the past three games.

"I've taken a lot of reps over there in the minor leagues and everything like that, so I feel good," McMahon said. "I love third base. I'd be lying if I said it doesn't feel like home, so I miss playing it a good bit.

"But, you know, we've got a pretty good player over there."

The Giants are dealing with injuries of their own, with backup catcher Chadwick Tromp landed on the 10-day IL on Tuesday because of a right shoulder strain.

San Francisco recalled Tyler Heineman from its alternative training site to serve as the backup to rookie Joey Bart.

The Giants did get some good news when X-rays on outfielder Alex Dickerson's right elbow came back negative after he was hit there in the ninth inning of the club's Monday loss to Colorado.

"I feel a lot better today," Dickerson said Tuesday. "It was really, really sore and tight last night. Today it's more just sore. A little bit of a range issue, but treatment's been going really well already. ... I think I'll just kind of play through some soreness here for a day or two, and it'll be al; right."

He felt good enough to hit a pinch-hit home run Tuesday, breaking a seventh-inning tie.

San Francisco outfielder Mike Yastrzemski increased his activity Tuesday, doing some light running on the treadmill. Yastrzemski hasn't appeared in a game since Thursday because of a strained right calf, but he has been playing catch and hitting off of a tee.

The hope is that Yastrzemski, the Giants' RBI leader with 33, can return to the lineup before the regular season ends.

--Field Level Media