SAN DIEGO -- On the verge of their first postseason in 14 years, the Padres welcomed their veteran first baseman back into the fold -- then tempered news of Eric Hosmer's return with a worrying revelation about their ace.

Right-hander Mike Clevinger, originally scheduled to start Saturday’s game against the Mariners, was scratched due to right biceps tightness. Luis Patiño, the club's No. 3 prospect, took the ball in his place and made his first big league start.

The Padres are confident that Clevinger, their prize Trade Deadline acquisition, will return to the rotation, potentially as soon as Tuesday. Manager Jayce Tingler noted that the team is merely playing it safe with its place in the playoffs all but wrapped up.

“We’re just being probably extra cautious more than anything,” Tingler said. “Just give it another couple days and go from there.”

Tingler estimated that Clevinger is at "85-90 percent" and added that he's "very confident" the injury wouldn't linger into the Padres' postseason pitching plans.

But in a way, maybe it already has. The Padres were seemingly lined up to start Clevinger in Game 1 of the Wild Card Series. It's unclear whether Saturday's news throws a wrench into those plans. (The Padres feel they have another ace in right-hander Dinelson Lamet. They'd be entirely comfortable flipping the two, and handing Lamet the ball for Game 1.)

In seven starts this season, including three with San Diego, Clevinger owns a 3.10 ERA. He's coming off a seven-inning shutout of the Giants last Sunday.

As for Hosmer, who missed two weeks with a fractured left index finger, his return is a boon for an offense that is already thriving. He's in the midst of his best season with the Padres, entering play on Saturday with a .288/.344/.542 slash line and eight home runs.

The Padres welcomed Tommy Pham back on Friday after he’d missed a month with a broken hamate bone in his left hand. Now, they seemingly have an overabundance of weapons -- particularly against right-handed pitching.

Both Hosmer and Pham started Saturday against the Mariners, and Mitch Moreland gave way in the starting lineup.

Catcher Francisco Mejía and right-hander Luis Perdomo were optioned to the team’s alternate training site to clear space on the roster for Hosmer and Patiño.