ST. LOUIS -- Tommy Pham and Magneuris Sierra may not know how long they will be with the St. Louis Cardinals, but they intend to make the most of the opportunity.
The two outfielders were called up from the minor leagues last week because of injuries that sent Stephen Piscotty and Jose Martinez to the disabled list and kept Dexter Fowler out of the lineup for six games.
That created playing time for Pham and Sierra, and all they have done is light a spark under the first-place Cardinals.
They did it again on Saturday against the Chicago Cubs as they each went 2-for-3, with Pham driving in two runs and Sierra one, to lead St. Louis to a 5-3 victory.
In the eight games he has played since being promoted from Triple-A Memphis, Pham is hitting .387 and seven of his 12 hits have gone for extra bases.
"When you are playing these good teams, you have to be at your 'A' game," Pham said. "A team like Chicago, we know how good they play us. I want to contribute any chance I get."
Pham has had stints with the Cardinals in the past, with limited success, but he believes there has been a difference this time since he joined the team.
"It's vision, it's mechanical, I'm trying to chase less and be more in the zone and when I get a good pitch to hit, I'm trying not to miss it," he said. "I felt like last year at the end of the season I got in trouble because I was chasing more and wasn't doing a good job hitting the fastball.
"Opportunities tend to create themselves, that's kind of how this industry works. I'm just trying to make sure I'm ready."
Manager Mike Matheny has been more than pleased with both how well Pham and Sierra have filled in for the injured players.
"I truly believe it's a vision thing," Matheny said of Pham. "He's constantly working with whatever he has to do to see the ball. He puts some great at-bats together, nice to see whatever he had to do to make those adjustments. It sounds simple enough but it can be very complex. He continues to have an impact around here."
His RBI single in the fourth inning followed a homer by Jedd Gyorko, his seventh of the season, which gave the Cardinals a 3-1 lead. He then doubled in another run in the sixth off reliever Pedro Strop and scored on a single by Sierra.
Sierra, called up from Class-A Palm Beach because he was the only outfielder on the 40-man roster who was not in the majors, also had a single in the fourth. Sierra, who is 8-for-20, has at least one hit in all five games he has played since joining the team last Sunday, and the Cardinals have won all of those games.
"He's unflappable," Matheny said. "He's going to be tested, the longer he's here, the more the league starts figuring him out. It's nice to have a player like that here. He's got a lot more in there. He's got a lot to learn but he's conscientious and he wants to learn."
The Cubs, dealing with their own injuries, promoted one of their top prospects, Ian Happ, from Triple-A Iowa on Saturday. Happ delivered his first career hit was a two-run homer, which cut the Cardinals' lead from 5-1 to 5-3 in the seventh.
Happ also was involved in a controversial play in the fifth when he was called for interference on a slide at second base, attempting to break up a double play. That out took a run off the scoreboard for the Cubs and left manager Joe Maddon upset.
"I have no idea why these rules are a part of our game," Maddon said. "Outs are rewarded based on a fabricated rule. It was created under the umbrella of safety. You slide directly over the bag and there's no chance for the runner to be thrown out at first, there was nothing dangerous on the part of our runner. I'm not into office-created rules. There was no malicious intent there whatsoever.
"I'm not blaming the umpire. Umpires do what they have to do. I think we have a tendency to micro-manage stuff that we have no business to do. Don't give me all protectionism stuff because I'm not buying into it. It's wrong."
Happ was not sure what had happened.
"I slid a little too far past the bag," he said. "I guess that's the rule, if you can't hold onto the bag, it's interference. That's what happened."
The homer came after what many on the Cubs thought should have been a single in the fifth, but was ruled an error on Matt Carpenter.
"It was a fun day," Happ said. "Losing stinks. There's no fun way to lose but to be in there and be around these guys and be a part of it was fun. It was a blast. I really enjoyed it. Besides a win, you can't ask for much more."
NOTES: In addition to his home run, RF Ian Happ reached on an error, walked and struck out in his major league debut for the Cubs. He was promoted from Triple-A Iowa on Saturday because of injuries to 2B Ben Zobrist and OF Jon Jay. Happ, 22, was the ninth overall pick in the 2015 draft. He is the fourth Cub to homer in his major league debut since 2010, joining Starlin Castro, Javier Baez and Jorge Soler. ... The Cubs opened a roster spot for Happ by optioning RHP Felix Pena to Iowa. ... Cardinals 3B Jhonny Peralta will begin a rehab assignment at Triple-A Memphis on Sunday. ... OF Magneuris Sierra made his home debut for the Cardinals, playing RF, a position he had not played since July 1, 2014, when he was in rookie Gulf Coast League. ... Saturday was RHP Michael Wacha's scheduled day to pitch for the Cardinals, but he will be skipped though this turn of the rotation and won't pitch until next Friday.