So far, our season-long “Stats All, Folks” feature has delved into sabermetric stats for hitting, pitching and fielding. But there’s one key facet of the game we haven’t yet considered: baserunning.

Let’s change that. For today’s edition, we’ll focus on BsR.

What is BsR?

No tricky acronyms here — BsR is simply an abbreviation for baserunning.

More specifically, BsR is a stat used by FanGraphs to measure a player’s or team’s skill at all aspects of baserunning — not just stealing bases, but also the ability to take the extra base on a hit, advance on a ball in play, and avoid getting doubled up.

When a runner pulls off a heads-up baserunning move, like going from first to third when an outfielder is slow to field a single, I’m sure you’ve heard announcers crow, “That’s the kind of play that doesn’t show up in the stats.” Well, now it does, thanks to BsR and other advanced baserunning statistics.

How is BsR calculated?

BsR takes three main skills into account: ability to steal bases, ability to advance on the bases, and ability to avoid grounding into double plays. Let’s consider them one at a time.

First, ability to steal bases. FanGraphs calls this wSB, or Weighted Stolen Base Runs. Put simply, this measures how many runs a player helps his team score by stealing bases — or how many runs he costs his team by getting caught stealing.

Obviously, stolen bases are great when they’re successful. That runner is 90 feet closer to the plate and makes his team likelier to score. But failed steal attempts are very damaging — they take a runner off the basepaths and add an out. In general, a runner needs to be successful in about 70% of steal attempts to have positive value for his team. Anything less than that, and he’s probably doing more harm than good.

Or as Earl Weaver famously put it, you don’t want “little fleas” who are “gettin’ picked off, tryin’ to steal, gettin’ thrown out, takin’ runs away from you.” (OK, so that was a tongue-in-cheek comment from a prank radio interview. But Earl had a point.)

The second component of BsR is the ability to advance on the bases, a stat with the rather dramatic-sounding name of Ultimate Base Running (UBR). This applies to almost any ball in play — i.e., does the runner advance a base on a groundout? Does he tag up on a fly out? How many bases does he advance on a hit? If he’s a trailing runner, does he move up a base when the lead runner does? Does he advance on a wild pitch or passed ball?

As any baseball fan knows, some runners are particularly good at taking the extra base, while others tend to plod around from station to station. On the other side of the coin, some runners are too aggressive and get themselves thrown out on the bases, while others are more conservative and tend to avoid running into outs. Basically, UBR measures how many runs a player adds or subtracts from his team through these types of baserunning plays.

For example, let’s say there’s a runner at second base with nobody out, and the batter hits a fly ball to medium-deep right field that’s caught for an out. If the runner tries to advance to third base and makes it, he’s made his team likelier to score, and his UBR would improve. If the runner tries to advance to third and gets thrown out, he’s made his team much less likely to score, which would hurt his UBR. And if he just stays put at second base, he wouldn’t move the needle much either way.

The third and final component of BsR is the simplest one — how often a player grounds into a double play, or Weighted Grounded into Double Play Runs (wGDP). It boils down to this: grounding into double plays is bad. (Yup, I’m going out on a limb on that one.) Slow runners, of course, tend to ground into more double plays than fast ones, since they’re not as quick down the first-base line. And wGDP calculates how many runs a player adds or costs his team by hitting into (or avoiding) double plays.

So those are your three components: wSB, UBR and wGDP. Add the three together, and voila! You have your BsR number.

BsR and the Orioles

We all know that the Orioles don’t steal bases. But aside from that, are they a good baserunning team?

Well, no. Not according to BsR. They rank 22nd of the 30 MLB teams in BsR this season, at -4.9. In other words, Orioles baserunners have cost the team nearly five runs this year, whether through bad decisions or just lack of speed.

That hasn’t always been the case, though. Last season, the Orioles had a positive BsR (1.8) that ranked 13th in the majors, even though they ranked dead last in MLB with 16 steals. So, a lack of stolen bases doesn’t always equate to being poor at running the bases.

What about individual Orioles? This season, so far, the highest BsR scores on the club belong to Manny Machado (2.4) and Joey Rickard (2.2). Stolen bases likely play a role in that — Machado is 4-for-5 in stolen base attempts, and Rickard is 5-for-6.

Several Orioles regulars, though, have negative BsR scores, including Jonathan Schoop (-3.2), Seth Smith (-2.7), Welington Castillo (-2.1) and J.J. Hardy (-1.9). That’s probably not surprising; none of those players is particularly fleet of foot, and they aren’t known for being aggressive on the bases. Hardy and Schoop, too, are hurt by their double play numbers. Schoop has grounded into a team-leading 10 double plays, and Hardy has hit into seven in 64 games.

In the span from 2014 to the present, the Orioles’ BsR leader is Adam Jones (7.8), which makes sense. He’s not really a stolen base guy — he has only 13 steals since 2014 — but he has good speed and tends to be smart about taking the extra base when it’s available.

The worst base runner since 2014 — again, not surprisingly — is Hardy, with a BsR of -7.9. Injuries and age have greatly hampered Hardy, who at this point seems to be the slowest runner on the team. He is prone to the double play, doesn’t steal bases (none in the last four years) and rarely advances on the basepaths.