CHICAGO -- Steven Souza Jr. made a successful return from a devastating left knee injury that cost him the entirety of last season. What the outfielder did not do was seize control of a role on the Cubs' bench.

Between doubleheader games against the Cardinals on Saturday at Wrigley Field, Souza was designated for assignment, following an injury-marred showing as a part-time outfielder with the Cubs. The roster move came after Souza struck out twice vs. Adam Wainwright in a 4-2 loss in Game 1.

The 31-year-old Souza was added over the offseason with the goal of being a right-handed complement to Chicago's predominantly lefty-swinging outfield. In 11 games, Souza hit .148/.258/.333 with one homer and five RBIs overall, with a 2-for-10 showing in a limited sample against lefties.

Souza returned from the 10-day injured list on Tuesday after a bout with a right hamstring injury. His return, however, coincided with the trade acquisitions of outfielder Cameron Maybin (via the Tigers) and designated hitter José Martínez (via the Rays).

The additions of Maybin and Martínez created a bit of a logjam within the Cubs' roster. On top of that, the Cubs were in need of some pitching insurance for Game 2, and recalled righty Tyson Miller from the alternate training site in South Bend, Ind., for the nightcap against St. Louis.

"We needed an arm," Cubs manager David Ross said. "And we've acquired some players that [have a] similar skill set as [Souza]. Just haven't been able to use him, with coming off an injury and a rough game in Pittsburgh [0-for-4 on Wednesday] and then the first one tonight. It just seemed like the right move for the group."

Cubs claim Vargas, among other moves
Prior to Saturday's doubleheader, the Cubs announced that they had claimed infielder Ildemaro Vargas off waivers from the Twins. Vargas has yet to report to the Major League club.

The 29-year-old Vargas -- a switch-hitter who has garnered most of his MLB action between second base and third base -- has hit .190 (.484 OPS) in 18 games this season between stops with the D-backs and Twins. In 92 games in '19, he hit .269 (.712 OPS) overall with a .340 showing (1.025 OPS) in 55 plate appearances against lefties.

Besides adding Vargas, the Cubs released right-hander Jharel Cotton and had righty Casey Sadler claimed off waivers by the Mariners. Chicago now has 59 players in its 60-player pool.

Childhood Cancer Awareness Day
For the fifth consecutive year, MLB and its clubs raised awareness for childhood cancer during all games on Saturday for a special league-wide day in home ballparks. MLB’s “Childhood Cancer Awareness Day,” held during Childhood Cancer Awareness Month in collaboration with Stand Up To Cancer (SU2C), combined a visual and ceremonial demonstration of support for the cause with outreach to local hospitals treating young patients in their communities. Childhood cancer is the leading cause of death by disease among children in the United States and Canada.

The Cubs joined all on-field personnel, including players, coaches and umpires around baseball in wearing gold ribbon decals and wristbands during Saturday's doubleheader against the Cardinals.

Clubs also featured ceremonial activities in ballparks. Club activities included pregame ceremonies, cardboard cutouts of pediatric patients in stands at ballparks, virtual patient first pitches, virtual player hospital visits and more.

Childhood cancer awareness efforts in previous seasons have included special pediatric cancer awareness batting-practice T-shirts, online campaigns to empower fans to hold fundraisers for pediatric cancer research and donations to local children’s hospitals. MLB and its clubs have supported the fight against cancer through a variety of initiatives for many years. As Stand Up To Cancer’s founding donor, Major League Baseball has pledged more than $50 million to SU2C’s collaborative cancer research programs, providing invaluable support. Launched in 2013, the work of the Stand Up To Cancer/St. Baldrick’s Foundation Pediatric Cancer Dream Team has helped to develop new immunotherapy approaches and contributed to the development of two new treatments for difficult-to-treat pediatric leukemias that have been approved by the FDA. MLB has recognized SU2C at its jewel events since the '09 World Series.

Worth noting
• Ross was happy that the front office was able to reach a deal with veteran reliever Pedro Strop, who is due to report to the team's alternate training site in South Bend, Ind., on a Minor League contract. The manager stressed, however, that the Cubs need to take a good look at whether Strop can impact the big league club.

"Pedro's been a big part of this group," Ross said. "One of my favorite teammates I've ever had. This guy is infectious, his personality, the way he carries himself, the way he works. He can really affect the room. But, ultimately, the goal is to get him back to being able to help us on the field, that's first and foremost."

• Ross noted that lefty José Quintana (10-day injured list, left lat) was scheduled to go through treatment on Saturday, following still feeling sore on Friday. The manager said Quintana would resume throwing Sunday at the earliest, and only if the soreness had dissipated.

• Righty Adbert Alzolay was called up from South Bend as the Cubs' 29th man to start Game 1 of Saturday's twin bill. The plan going into the day was to have righty Colin Rea come out of the bullpen to start Game 2 against St. Louis.