Jay Bruce is an interesting player these days, for reasons you know and reasons you may not. He's interesting because after more than a decade in the Cincinnati organization, he's been traded four times in the last three years, including from Seattle to Philadelphia less than two weeks ago.

He's interesting because his stunning power barrage as a Phillie -- five homers in his first seven games -- earned him his first Player of the Week award in nearly seven years, and because injuries and suspension issues in the Philadelphia outfield suddenly make him a vital part of a team trying to win the NL East.

Those items alone are a good start, but there's a lot more here. We dug up two more fascinating facts that you need to know about Philadelphia's unexpected slugger.

1) He's more proof that batting average isn't the right way to judge a hitter

It's 2019, so it's not exactly news that looking at a hitter's batting average as a judgment of his offensive production isn't exactly the right way to do things. Walks matter, and extra-base hits are more valuable than singles. Nothing controversial there. Bruce has long been a low-average, high-power kind of hitter, and that hasn't changed this year.

What's different, however, is the extent to which he's taking this. Bruce is hitting .232, which is tied for 138th of qualified hitters. It's similar to Rio Ruiz and Freddy Galvis. It's ... not great. It's easy to say "he's hitting .232, he's having a lousy year," and be done with it.

It's also not accurate. While Bruce's .294 OBP is poor, his .586 slugging percentage is outstanding, tied for 16th among qualified hitters. He's outslugging Javier Baez, Daniel Vogelbach, and Anthony Rizzo. He's mashing, to the point that his OPS+ -- a park-adjusted stat where "100" is read as "league-average" -- is 131, meaning he's been 31 percent better than an average hitter. While someone like David Fletcher may have a .306 average, his slugging is 154 points lower, so his OPS+ is 114, meaning Bruce has been more valuable.

That's probably hard for many to accept, but it's long been proven that OPS has a much stronger relationship to run scoring than batting average does, so it matters. Still, even for those of us who don't care much about batting average, .232 is a pretty low number to have for an above-average hitter. It's hard to have an average that low and still be this good. It is, as it turns out, nearly impossible.

Thanks to Baseball-Reference, we were able to look at the 3,365 qualified seasons in Major League history with an OPS+ of at least 131, as Bruce had entering Friday's games. Then we sorted them by lowest batting average.

Lowest batting average with OPS+ of at least 131, all-time

.224 (134 OPS+) -- Gene Tenace, 1978
.227 (133 OPS+) -- Carlos Pena, 2009
.231 (138 OPS+) -- Harmon Killebrew, 1972
.232 (131 OPS+) -- Jay Bruce, 2019
.233 (134 OPS+) -- Gene Tenace, 1977

What Bruce is doing has just about never been done. You don't do this on purpose, obviously. If you were to ask him, he'd surely say that he'd love to be hitting .300. Every hitter would. But don't confuse a low average with a poor season. While it may be coming in an unconventional way, Bruce has been one of the better hitters in the game this year.

2) No one has added more running speed since last year

Bruce has never really been known for his speed, though he did steal 12 bases back in 2014, and in 2016, he was essentially a league-average runner. We measure that with the Statcast metric Sprint Speed, which tracks running speed in feet-per-second in the fastest one-second window, aiming to capture the time when a runner is moving his fastest. The Major League average is 27 feet per second.

Three years ago, Bruce was about average. Then it went downhill.

2016 -- 26.8 ft/sec -- 49th percentile
2017 -- 26.3 ft/sec -- 37th percentile
2018 -- 25.5 ft/sec -- 23rd percentile

That 23rd percentile means that about three-quarters of players were faster, and that's of all players, including catchers and first basemen. Looking just at right fielders, Bruce was 61st ... of 61. Not a single one was slower.

That's partially because of age, as Bruce is now 32 years old, and partially because he was never a burner to begin with, but there's also a much clearer reason: Health. Bruce missed time early in the season with a case of plantar fasciitis in his left foot, had some back discomfort in early June, then missed more than two months with a right-hip injury. Taking all that into account, it's not surprising his running speed suffered. It would have been a surprise if it hadn't.

Now, take a look at Bruce in 2019.

2019 -- 26.8 ft/sec -- 51st percentile

Bruce is back up exactly to where he was back in 2016, when he was a league-average runner. Gaining back that missing 1.3 ft/sec is such a big deal, in fact, that no regular player has added more speed since 2018.

As we detailed last season when we noted Matt Kemp had added a great deal of speed back, this appears to so often be about health. Yangervis Solarte had an oblique problem last year. George Springer specifically talked last winter about losing weight to add speed. Eduardo Nunez detailed how his 2017 knee injury affected him early in 2018.

The point here isn't really about speed, because that's not Bruce's game. The point is about health, because a hobbled Bruce hit only .223/.310/.370 with nine homers last year. Compare that to 2016-17, when he hit a combined 69 homers with a .507 slugging percentage. It doesn't matter so much if he can run, but if these numbers can tell us that he's healthy enough to mash, it's a big deal.

And wouldn't you know it: Bruce's hard-hit rate is way, way up.

It's a huge jump, up from last year's 34.4 percent (a below-average 35th percentile) to 43.7 percent, an above-average 74th percentile. Bruce's hard-hit rate is better than Mookie Betts, Manny Machado, or Francisco Lindor.

And, wouldn't you know it, look how he's applying that hard-hit rate: In the air. Only one qualified player, Minnesota's Jorge Polanco, has a lower ground-ball rate than Bruce's 25 percent.

Bruce isn't going to keep hitting homers like he's done so far in Philadelphia, of course. But he might keep mashing with a low average, because that's sort of his game. He's hitting the ball hard, and he's hitting in the air. So long as he does, the Phillies will take it.