La Stella, 26, was a member of Chicago's Opening Day roster but was placed on the disabled list on April 14 with a right oblique strain first suffered on April 10 and re-aggravated in May. He saw action in two games with the Cubs prior to his initial injury, going 1-for-6 (.167). He batted .250 (9-for-36) with three doubles and three RBI in 10 games covering a pair of rehab assignments with Double-A Tennessee before being activated from the disabled list and optioned to Iowa on August 11, where he has hit .333 (11-for-33) with one homer and six RBI in nine games.
The left-handed hitter was acquired from Atlanta for pitcher Arodys Vizcaino last November 16. La Stella made his major league debut with the Braves last season and led National League rookies with 36 walks and a .328 on-base percentage (min. 300 plate appearances). In 93 games, he hit .251 (80-for-319) with 16 doubles, one home run and 31 RBI, and compiled a .984 fielding percentage (6 E/368 TC) in 88 games at second base.
Rosscup, 27, joins the Cubs for the second time this season as he went 2-1 with a 4.30 ERA (11 ER/23.0 IP) in 26 relief appearances before being placed on the 15-day disabled list on June 17 with left shoulder inflammation. He was activated from the disabled list and optioned to Iowa on August 14. With the Cubs, Rosscup has struck out 25 batters in 23.0 innings while limiting foes to a .241 batting average, including a .111 average (3-for-27) and .384 OPS by left-handed hitters.
With Iowa this year, Rosscup has posted no record with a 7.36 ERA (6 ER/7.1 IP) in eight relief outings, fanning 13 hitters in 7.1 innings pitched. A season ago, Rosscup went 1-0 with a 9.45 ERA (14 ER/13.1 IP) in 18 appearances covering seven stints with the Cubs, striking out 21 batters in 13.1 innings pitched. Overall, Rosscup is 3-1 with a 5.44 ERA (26 ER/43.0 IP) in 54 relief appearances with the Cubs covering the last three seasons (2013-15).
Soler, 23, is batting .265 (91-for-343) with 18 doubles, seven home runs and 42 RBI in 90 games with the Cubs this season. This marks his second stint on the disabled list this season, as he was sidelined from June 3-July 5 with a sprained left ankle.
Motte, 34, is 8-1 with nine holds, six saves and a 3.91 ERA (21 ER/48.1 IP) in 57 relief appearances for the Cubs this season.