Trade grades: Cubs add depth with Justin Wilson, Alex Avila

— -- ? ESPN Insider will provide trade grades for every deal before Monday's 4 p.m. ET deadline.

The trade

Chicago Cubs acquire:?LHP Justin Wilson, C Alex Avila
Detroit Tigers acquire:?3B Jeimer Candelario, SS Isaac Paredes, plus cash or a player to be named

Chicago Cubs: A

The Cubs add some much-needed secondary parts not only to help fend off the Milwaukee Brewers in the National League Central (that lead is up to 2? games), but to improve their chances against the Nationals and Dodgers in the postseason.

Wilson is the key guy: A power lefty who is under team control through 2018. He has 13 saves for the Tigers and has dominated this season, holding batters to a .156 average. His fastball averages 96 mph and he mixes in a cutter that has actually made him tougher against righties the past couple of seasons as well as a slider he uses against lefties. This is no LOOGY; this is a guy you can use against the meat of the order in a crucial situation.

Avila becomes the backup to Willson Contreras. He has had a strong season at the plate with an .869 OPS, though he has slumped in June. It's a good trade for the Cubs not only because they added two nice pieces, but they didn't surrender anyone who fit on the roster in the near-term future.

Detroit Tigers: C

The Cubs had no room for Candalerio -- some guy named Kris Bryant blocked his path -- and he certainly has some offensive tools, hitting .266/.361/.507 at Triple-A Iowa at age 23 (and had even better numbers there last year in 300 at-bats). I think he has been a little overhyped as a prospect -- had him as the Cubs' top prospect after the trade of Eloy Jimenez, as he seems to be a player with a high floor compared to a high ceiling. He's viewed as an average defensive third baseman, which would be a big edge over the awful Nick Castellanos.

Paredes is an 18-year-old holding his own in the Midwest League, has some power potential, but probably doesn't stick at shortstop. If you look at Candalerio, it's a solid return for Detroit, but Wilson is probably the top reliever available and I thought the Tigers could do a little better for him and Avila.