The 38-year-old Ross is batting .189 (20-for-106) with seven doubles, one home run and seven RBI in 51 games with the Cubs this season. Ross owns a 2.63 catchers ERA (78 ER/267.1 IP) in his 40 games (31 starts) behind the plate, with the Cubs posting a 20-11 record in his starts.
Szczur, 26, is batting .217 (13-for-60) with four doubles, one homer and eight RBI in 35 games with the Cubs this season. He has batted .295 (66-for-224) with 10 doubles, two triples, seven home runs and 26 RBI in 58 games this year.
La Stella, 26, has been on the disabled since 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. The Cubs acquired La Stella from Atlanta last November 16 for righthander Arodys Vizcaino.