Back when the Detroit Tigers acquired Yoenis Cespedes from the Boston Red Sox as the main piece in the Rick Porcello last December, some fans simply didn’t know what to think. After all, Porcello was coming off of a great year, going 15-13 with a 3.43 ERA and a 1.23 WHIP, and it was becoming a real concern that Cespedes may have peaked during his rookie season with the Oakland Athletics back in 2012.

With only two weeks left to go until the 2015 MLB All-Star game, however, the deal has turned out to be a big win for team Dave Dombrowski and the Tigers. Porcello has struggled in his first season with the Red Sox, going just 4-8 with a 5.54 ERA and a 1.36 WHIP. He has also seen his ground ball rate fall to 43.8 percent, which would be a career low if the season ended today.

Cespedes, on the other hand, may be on his way to having his best season to date. At the plate, he is hitting .300/.330/.495 with 10 home runs and 42 RBIs. He still isn’t a very patient hitter, walking only 4.6 percent of the time, but he has been making a lot of solid contact, and his .355 BABIP helps to explain why his BA is well above his career mark of .269.

On defense, Cespedes has been terrific as well, posting a 14.6 UZR/150 with nine DRS for the Tigers in left field this season. His arm has been extremely impressive as well.

Cespedes already has seven assists, tying Chris Coghlan of the Chicago Cubs for the MLB lead among left fielders. He also currently ranks seventh among all qualified outfielders in the AL with a 2.5 fWAR, which is a great illustration of just how valuable he has been overall.

Of course, Porcello still has the talent to turn his season around, but right now it is fair to say that the deal has worked out better for Detroit in the first half of the 2015 MLB season. Plus, the Tigers also got Alex Wilson in the trade, and he has turned out to be a real pleasant surprise in his own right.

Cespedes’ First-Half Grade: A

Brad Faber is a Senior Writer and Sabermetrics Columnist for www.RantSports.com. Follow him on Twitter @Brad_Faber or “Like” him on Facebook