This past Saturday, after participating in the first regular season re-match of the All-Star Game's starting pitchers, Matt Harvey felt some discomfort in his forearm, later revealed to be a torn ulner collateral ligament. If you are wondering why your Mets-fan friends are upset, read on.

Mets general manager Sandy Alderson has embraced the "stars and scrubs" philosophy of rebuilding the Mets, but when your stars are injured you are left with only the scrubs. Fangraphs editor-in-chief Dave Cameron made him the highest-ranking pitcher on his annual trade value leaderboards, and Harvey's performance this season as a pitcher was the fourth best overall since 1969, behind only Pedro Martinez's other-worldly performance in 1999 and two other Mets heroes, Dwight Gooden and Tom Seaver. Why use FIP (Fielding Independent Pitching) as a measure of Harvey's worth, rather than a more traditional stat? FIP offers a measure of the factors of the game a pitcher can control—and this is important since the fielders behind Harvey this year were journeyman at best. Aside from fellow All-Star David Wright (also injured this past month, and possibly lost for the year) and recently promoted Travis d'Arnaud (the main return in last year's R.A. Dickey trade), the team behind Harvey was filled with players who would not make another Major League roster, much less start.

Will Carroll, one of the (if not the) pre-eminent independent expert on sports injuries, wrote a column this summer praising the Mets analytics-based approach to minimizing the risk of a Harvey injury:

The Mets are trying to use more evidence-based measures than most teams... A team source told me that the team has milestones set up at 170, 190 and 210 innings. At those points, they will check Harvey's fatigue levels, velocity, release point and pitch movement. The Mets are doing their best to be as objective as possible... The downside is that even if the Mets had purely objective measures, there's really nothing to compare them with. Baseball doesn't know how to handle young pitchers, as the sheer number of wrecks alongside the bullpens show. An educated guess like they're trying to make with Harvey is still a guess.

Because Major League Baseball makes velocity, release point, and pitch movement data publicly available, we can try and reproduce the measures that Carroll's sources suggested the Mets were using to gauge Harvey's fatigue using BrooksBaseball.net's Matt Harvey "Card." By my own (amateur, obviously) inspection, his velocity was indeed slightly down, but still above where it was earlier in the year, and his release point remained consistent, as made internet baseball nerd famous by the amazing GIF illustrating a story about Harvey's "nearly perfect" performance. On Grantland, Jonah Keri notes that his release rate did drop a little less than an inch in August, but otherwise his pitching was still incredibly efficient.

There is a silver lining for Mets fans. The full extent of the injury is not known, and Carroll cautions Mets fans not to overreact. If Harvey does need surgery, he should come back the same pitcher he was, and in fact 1 in 3 Major League Pitchers have had the surgery that is considered his worst case outcome. And we'll always have the Jimmy Fallon video in which casual Mets fans fail to recognize Harvey as an on-the-street reporter. Something tells me those days are over.