Kansas City Royals catcher Salvador Perez injured his UCL joint and may need Tommy John surgery, according to Jeff Passan of ESPN:

Perez, who will turn 29 in May, is one of the lone holdovers from Kansas City's 2015 World Series team, winning the World Series MVP that year.

One of the best defensive catchers in the game, Perez has won five Gold Gloves while making six straight AL All-Star teams. He also ranks sixth in fWAR among catchers from 2013-18.

Perez is coming off consecutive seasons with 27 homers and 80 RBIs, establishing himself as a major-producer in an otherwise lackluster Kansas City lineup.

In the 2015 postseason, Perez was truly magnificent. He clubbed four homers and drove in eight runs in the playoffs while hitting .364 in the World Series on his way to MVP honors. Perez also hit .333 in the 2014 World Series.

This is yet another setback for a Royals team desperately trying to rebuild. Kansas City missed the playoffs in 2016 after winning the World Series, becoming the fourth-straight reigning champion to miss out on October the following season.

Lorenzo Cain and Eric Hosmer left the team last offseason in free agency, and the Royals also shipped Mike Moustakas to the Milwaukee Brewers before the trade deadline.

Certainly there have been bright spots. The Royals extended Whit Merrifield after he led the majors in hits (192) and stolen bases (45). Adalberto Mondesi hit 14 homers and stole 32 bases in just 75 games last season as a 22-year-old, and he looks like the potential future of the organization.

Kansas City was not going to be a winning team this season, but should they lose Perez for the season, they will also be losing a veteran presence in a clubhouse full of young and developing players.