Stats show why Sanchez 'is not for sale'

Gary Sánchez for J.T. Realmuto, who says no to that trade? The Yankees, it sounds like.
In an interview with YES Network that will air Monday at 6 p.m. ET, Yankees general manager Brian Cashman did his best to quash the notion that the Bronx Bombers are looking to move their catcher -- in contrast to a report from MLB Network insider Jon Heyman earlier this week saying that New York would be willing to trade Sanchez in a package for Realmuto.
"I have been asked about Gary Sanchez," Cashman says in the interview. "He's not for sale."
• Cashman: Sanchez rumors 'completely false'

The Yankees see Sanchez as the developing superstar who crushed 53 home runs and recorded a .923 OPS in 175 games from 2016-17 -- not the player who struggled to a .697 OPS in 2018 and batted below the Mendoza Line.
And there's reason to believe they're right. Here's why:
Sanchez has elite tools
Sanchez can crush the ball like few other players, let alone catchers. Hitting the ball hard is an important skill -- players who can hit the ball hard consistently are more likely to get hits and do damage. That's where exit-velocity data from Statcast™ comes in.
Statcast™ categorizes batted balls into six levels of contact quality. The very best are "barrels" -- batted balls with ideal combinations of exit velocity and launch angle. They're the type of hit most likely to go for a home run or an extra-base hit. Sanchez barreled 13.9 percent of his batted balls in 2018, 15th highest of 281 hitters who put at least 200 balls in play. And 8.6 percent of his plate appearances ended with him barreling the baseball, tied with fellow Baby Bomber Aaron Judge and National League Rookie of the Year Ronald Acuña Jr. for 16th best in MLB.
Sanchez puts up extreme exit velocities more often than almost any hitter. He hit the ball 110 mph or harder on 10 percent of his batted balls, sixth highest in the Majors, and in 6.1 percent of his plate appearances, seventh highest. And that doesn't include the 114.8 mph, 479-foot home run he crushed against the Red Sox in the postseason -- his hardest homer of the year. Sanchez reached a maximum overall exit velocity of 121.1 mph -- on an extraordinarily unlucky lineout at Yankee Stadium on June 19 -- making him one of just three players since Statcast™ began tracking in 2015 to drive a ball in the air at an exit velocity of 120-plus mph. Yes, all three are Yankees: Judge, Sanchez and Giancarlo Stanton.
Realmuto, by comparison, barreled 9 percent of his batted balls, and 6.4 percent of his plate appearances resulted in a barrel. He didn't once reach the 110 mph mark, topping out at an exit velocity of 109.8 mph.
And that's just Sanchez's offensive weapons. He also remains one of the strongest-armed catchers. Sanchez's average pop time to second base on steal attempts was 1.94 seconds in 2018, tied for third-best among regular catchers. His average max-effort arm strength was 86.8 mph, ranking fourth. Though those numbers rank among the best, Realmuto does get the edge here, ranking first with a 1.9-second average pop time and second with an arm strength of 87.8 mph.

Sanchez underperformed his expected metrics
Sanchez's stat sheet looked ugly this season: a .186 batting average, .406 slugging percentage and .304 weighted on-base average (an overall measure of offensive performance scaled like on-base percentage). But he actually made better contact than those numbers suggest. He wasn't hitting at his lofty 2016-17 standards, but it also wasn't as bad as it looked.
Statcast™ gives an "expected" version of each of those statistics, based on how well a hitter struck each ball instead of the result he got in the box score. Sanchez had a significant gap in all three, but most significantly in his expected slugging and his expected wOBA. His xSLG was .468 -- a huge 62-point difference that was one of MLB's largest, suggesting he could have easily done a lot more damage.
And most telling from a holistic standpoint, his expected wOBA was .343 -- again, nearly 40 points better than what he ended up with. The "unlucky" gap between his expected and actual wOBA was the 10th largest of 312 hitters with at least 250 plate appearances in 2018.
League-average wOBA was .315 in 2018, and league-average xwOBA was .311. Sanchez was making contact like an above-average hitter.

Sanchez was playing through a shoulder injury
This is the elephant in the room. Sanchez was playing through a left shoulder issue that necessitated offseason surgery to remove debris from his AC joint. His shoulder had been an issue since the end of 2017, when he received the first of a series of injections to address discomfort.
"Once that shoulder declared itself as a continuing problem, and he ultimately had to have surgery on his non-throwing shoulder, I think that probably gives us all a little bit more insight about some things he was dealing with that contributed to the numbers being down lower and lower," Cashman said in the YES interview.
That certainly seems like it could be a root cause of some of Sanchez's struggles at the plate. He's expected to be ready for Opening Day, and a healthy Sanchez should be a difference-making Sanchez. He showed flashes of how dangerous he can be even while he was playing through the issue. If he's fully recovered come 2019, a return to form could absolutely be in store.