ST. LOUIS -- The Padres weren’t really sure what they were going to do with Vince Velasquez after they signed him to a Minor League deal last weekend, not long after the Phillies released him.

All they knew is they needed pitching and they needed it now.

“I was pretty much told I was going to be a reliever, then I was going to be a starter,” Velasquez said after his Padres debut Friday night in an 8-2 loss to the Cardinals at Busch Stadium.

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Yet another pitching injury took care of that bit of uncertainty. When Blake Snell went on the injured list with a left adductor strain, a door opened for Velasquez to try to salvage his career as a starting pitcher and for the Padres to stabilize their rotation. Velasquez is the second struggling starter the Padres have been prompted to sign as their season approaches its climax.

Like Jake Arrieta before him, Velasquez struggled to provide the Padres many early answers. Velasquez allowed two early home runs as the Padres fell 1 1/2 games behind St. Louis in the race for the second National League Wild Card spot.

“I’m definitely grateful for the opportunity to be here, knowing this team has lost a couple starters in the rotation,” Velasquez said. “Not the best display to come out and help them out. But there’s definitely some positives in this, and I feel like not walking any guys today was definitely a big plus.”

Trouble started early for Velasquez. Tommy Edman yanked Velasquez’s fifth pitch as a Padre into the right-field corner, past a diving Eric Hosmer. Two batters later, Tyler O’Neill finished a 10-pitch at-bat by cranking a low missile over the Padres’ bullpen for a home run that gave St. Louis a 3-0 lead. Rookie Dylan Carlson later added a solo home run off Velasquez, who had retired 11 batters in a row before that.

Velasquez lasted four innings. Arrieta, who has pitched to an 8.25 ERA since joining San Diego, is scheduled to pitch Sunday, the final game of a series that will help sort out the NL Wild Card race as the season approaches its final two weeks.

The Padres are hopeful they will get injured pitchers Snell and Chris Paddack back sometime next week. How much longer they go with Velasquez and Arrieta figures to depend on the health of those two pitchers. Velasquez could be headed to the bullpen if Snell or Paddack comes back next week.

“I think that’s safe to say, of course,” manager Jayce Tingler said. “Besides the first three batters of the game, I thought he had a real good game and, certainly, one to build on.”

The Padres aren’t the only team with Wild Card aspirations who were forced to shift on the fly to find pitching answers. The Cardinals, who have been without ace Jack Flaherty most of the season and promising young starter Dakota Hudson all year, traded for 30-somethings Jon Lester and J.A. Happ on July 30 to shore up their pitching. They’ve had better results than the Padres’ pair. Lester and Happ, who opposes Arrieta on Sunday, have combined to go 7-3 with a 4.12 ERA in 89 2 /3 innings for St. Louis.

San Diego’s offense, which snapped out of a lengthy hitting funk over the previous two games in San Francisco, struggled to get much traction against St. Louis starter Miles Mikolas, who allowed just three hits in 5 2/3 shutout innings. The Padres managed to score twice off the bullpen in the seventh inning, with Jake Cronenworth and Jurickson Profar driving in runs. The game got out of hand when the switch-hitting Carlson, batting right-handed this time, launched a grand slam off Ross Detwiler.

The Padres made nine groundouts Friday on balls hit to the pull side, feeding a trend that Tingler finds troubling. He had talked about the team’s more all-fields approach in San Francisco, where they scored 16 runs in the final two games of the series.

“We’ve definitely got to get back to longer at-bats and hitting the ball the other way,” Tingler said. “No doubt about it, the common theme for the two games before that was avoiding those, understanding that pull side on the ground is death.”