Grimm, 26, returns to the Cubs after landing on the disabled list on April 10 with right forearm inflammation. He made one rehab appearance as part of his return, tossing a scoreless inning with a walk and two strikeouts on Monday for Iowa at Nashville. Grimm made Chicago's Opening Day roster for the second season in a row but has yet to make his 2015 debut.
The righthander went 5-2 with 11 holds and a 3.78 ERA (29 ER/69.0 IP) in 73 relief appearances last year with the Cubs, his first full season in the majors. Grimm tied for ninth in the National League in appearances while striking out 70 batters and walking only 27 in 69.0 innings. Overall, Grimm stranded 25 of 30 inherited runners last year and posted a 2.60 ERA (8 ER/27.2 IP) in 29 games following the All-Star break.
Grimm joined the Cubs as part of the five-player deal that sent pitcher Matt Garza to the Texas Rangers on July 22, 2013. He was the American League Rookie of the Month with Texas in April, 2013 and posted a 2.00 ERA (2 ER/9.0 IP) in 10 relief appearances with the Cubs following the trade that summer.
Szczur, 25, joins the Cubs for the second time this season, as he was a member of Chicago's Opening Day roster and batted .200 (2-for-10) with one double and one RBI in eight games before being optioned to Iowa on April 19. With Iowa, Szczur has batted .262 (11-for-42) with two homers, a triple and seven RBI in 11 games this season.
The outfielder made his major league debut with the Cubs last August and batted .226 (14-for-62) with two doubles, two home runs and five RBI in 33 games. Szczur has played 14 games in left field, nine games in center field and 13 games in right field during his big league career. Overall, he has batted .222 (16-for-72) with three doubles, two home runs and six RBI in 41 career major league games.
Lake, 25, is hitting .286 (4-for-14) with one double and one RBI in four games with the Cubs this season. He is batting .289 (13-for-45) with two doubles and eight RBI in 13 games with Iowa this year.
Varvaro, 30, was claimed off waivers from Boston on Sunday, was added to the 25-man roster yesterday and did not appear in the game last night. He was traded to the Red Sox last December 17 and went 0-1 with a 4.09 ERA (5 ER/11.0 IP) in nine relief appearances this season before being designated for assignment on April 29.