ST. LOUIS -- The Cardinals added a pair of pitchers -- left-hander Marco Gonzales and right-hander Sam Tuivailala -- to their roster ahead of Tuesday's doubleheader against the Brewers, while also sending infielder Paul DeJong back to Triple-A Memphis.
Tuivailala takes DeJong's spot on the Cardinals' 25-man roster. Gonzales, who will start Tuesday's nightcap, joins the club just for the day. Per Major League rules, clubs are permitted to add a 26th player to their roster for a doubleheader.
The Cardinals also announced that they have granted infielder Jhonny Peralta his unconditional release. The Cards were not able to find another team interested in trading for Peralta after he was designated for assignment on Friday. By releasing him, St. Louis is obligated to pay the remainder of his $10 million season salary.
Gonzales' start on Tuesday will be his first in the Majors since 2015. He missed last season due to injury, and he returned from Tommy John surgery in May. After making one start for Class A Advanced Palm Beach, Gonzales moved up to Memphis, where he had a 3.26 ERA, 1.154 WHIP, 24 strikeouts and nine walks in five starts.
Tuivailala has shuttled back and forth from Memphis to St. Louis four times this season. He's appeared in 10 games with the Cardinals and posted a 3.27 ERA over 11 innings. Tuivailala has five saves and a 1.65 ERA in 14 games with Memphis.
"I think there's just a whole lot of opportunities when you're looking at the middle of the game," Cardinals manager Mike Matheny said of Tuivailala's role. "We will just kind of wait and see how he fits in and how he takes advantage of the opportunities he gets."

DeJong made an instant impact upon being summoned to the Majors in late May. He homered in his first at-bat and tallied hits in six of his first 15 at-bats. But DeJong, who struck out 13 times and didn't draw a walk in 41 at-bats, had been squeezed out of playing time upon Kolten Wong's return from the disabled list.
"[With the] doubleheader, we need pitching, too, and that always makes a difference," Matheny said of sending DeJong down. "But if he's not going to get consistent starts, he needs to go to Triple-A."
A new addition
Matheny became a grandpa on Tuesday after the wife of his oldest son, Tate, gave birth to a boy, Ryker James. Ryker and his mom, Margaret, are said to be doing well.