"Bass gives us that length we need if something happens," said Padres manager Bud Black.
The Padres needed eight innings from their relievers in Sunday's 15-inning victory over the Cubs. Two days earlier, they needed 8 1/3 innings after Edinson Volquez was hit hard early and didn't finish the first inning against the Cubs. Volquez was designated for assignment the following day.
As for Bass, this is his third stint with the Padres this season. Bass, 25, was on the Opening Day roster but was optioned to Tucson after posting a 4.55 ERA in 18 games. He was 4-6 with a 5.45 ERA in 15 starts with Tucson and was 2-2 with a 2.30 ERA in his last five starts.
"I've been trying to figure things out mechanically, and I've decided to go with what works for me," Bass said. "I've gone back to what got me here in 2011 -- pitching from the third-base side of the rubber -- and I have added more coil to my delivery.
"But mostly it's been having conviction in my pitches. That's something I was lacking."
Bass had a 1.68 ERA in 48 1/3 innings in 2011 and was 2-8 with a 4.73 ERA in 97 innings last season. He can pitch in long and short relief and could certainly make a spot start, if needed.
The Padres have yet to name a starting pitcher for Wednesday's series finale against the D-backs. That pitcher will take the spot of Volquez.
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.