By Bruce Levine–

CHICAGO (CBS) — Not satisfied with the entire composition of their roster, the Cubs made an under-the-radar move Saturday, claiming catcher Rene Rivera off waivers from the Mets.

With starting catcher Willson Contreras on the shelf for at least several more weeks with a hamstring injury, the Cubs front office was looking to tighten up the team’s defense. Rivera is well-regarded for his defensive capabilities, with an advance National League scouting saying he has the ability to shut down opposing teams’ running games so long as he gets help from the pitchers as well.

Rivera has thrown out he’s thrown out 32.3 percent of runners for this season and his entire career, a mark that would tie for the best in the National League this year if he qualified.

The Cubs face the Reds, who have the third-most stolen bases in MLB, in a three-game series starting Tuesday. To make room on the 25-man roster, rookie catcher Victor Caratini will likely be sent to Triple-A Iowa for a short time before being called back up when roster expand Sept. 1.

The Cubs and Mets had previously discussed a deal for Rivera in July before Chicago acquired catcher Alex Avila from Detroit, a source confirmed.

“He is very good,” Cubs manager Joe Maddon said of Rivera. “He has a great reputation and he is a nice fellow, very good defensive player. He has some pop also. He will hit a couple of home runs. He brings that veteran presence. The depth that it provides is all good stuff.”

Rivera will either join the Cubs in time for a series finale against the Blue Jays on Sunday at Wrigley Field or meet the team in Cincinnati ahead of the start of that series Tuesday.

The 34-year-old Rivera is a nine-year veteran who’s hitting .230 with eight homers and 23 RBIs in 54 games this season. He’s a career .215 hitters.

To make room for Rivera on the 40-man roster, the Cubs designated 27-year-old right-hander Aaron Brooks for assignment.

Bruce Levine covers the Cubs and White Sox for 670 The Score and CBSChicago.com. Follow him on Twitter @MLBBruceLevine.