The Tampa Bay Rays have overtaken the Arizona Diamondbacks for first in the league in BaseRunning (BsR) at Fangraphs.com. The Rays have managed to be worth +20.7 runs, but they don’t do it the way that you would think a good base running team does it. However, they have added over two wins on the bases.

BsR is broken down into three components. BsR is the total of Weighted Stolen Base Runs (wSB), Weighted Grounded Into Double Play Runs (wGDP), and Ultimate Base Running (UBR).

Weighted Stolen Base Runs is like it sounds. The linear weighted run value of stolen bases minus the weighted run value of outs made attempting a stolen base. The Rays are 11th in the majors with 63 stolen bases. Do to being caught 25 times the Rays have been slightly negative at -0.3 wSB. The range from best to worst is +5.0 (Cincinnati Reds) to -4.9 (Chicago White Sox).

The Rays have been strong in the second component of Weighted Grounded Into Double Play Runs. Weighted Grounded Into Double Play Runs is the linear weighted value of runs created or lost when a player has the opportunity to hit into a double play. The Rays have been worth +2.0 wGDP ranking sixth in MLB. Their elevated strikeout rate and below average groundball rate is the primary cause of these saved runs. The Minnesota Twins lead the league with +6.1 wGDP while the Toronto Blue Jays and Baltimore Orioles have a league worst -5.3 wGDP.

The third component is where the Rays have excelled.

Ultimate Base Running is based on the value of taking the extra base or getting thrown out trying to advance on the bases. The primary example would be going from first to third on a single or second to home on a single. The Rays have led the league with a +19.0 UBR. The Diamondbacks come in second at +12.3 UBR. The New York Mets lag the league with -19.3 UBR.

Sometimes the Rays make frustrating outs on the bases, but they push the envelope more than any team in baseball.

On the individual level the breakdown for the Rays is quite interesting.

Who would be the player you think would lead the team? Kevin Kiermaier. Maybe Mallex Smith has done enough in his short time in the majors.

The team leader is 1B Logan Morrison with a +4.9 BsR. Not the first guy you think of, but he has excelled at getting reads and taking the extra base. His +4.3 UBR is the fifth highest in the majors. The other +0.6 comes from wGDP.

Kevin Kiermaier comes in second and would likely lead the team if he didn’t miss most of the last two months. Kiermaier’s +4.4 BsR breaks down to +2.6 UBR, +1.6 wGDP, and +0.2 wSB. He is currently rehabbing in Port Charlotte, set to begin playing games on Sunday.

Sometimes the Rays make frustrating outs on the bases, but they push the envelope more than any team in baseball.

The leaner and speedier 2017 version of Corey Dickerson comes in third at +3.9 BsR. Like Morrison, most of Dickerson’s value has come from taking the extra base. Dickerson’s +3.8 UBR is the eleventh highest total in the majors. He adds +1.0 wGDP, but has been worth -0.9 wSB. Most of the runs there likely come from unsuccessful hit and runs.

Mallex Smith is a player you would expect to be higher on the boards despite his limited playing time. There have already been runs scored due to the Mallex Effect, and he leads the Rays with 16 swiped bags. His +1.4 wSB leads the team which is tied for the 19th best total in the majors despite only having 201 plate appearances. Smith has added +0.4 wGDP, but has over boogied on the bases and been worth -1.1 UBR.

Sometimes the Rays take gambles that might be reckless or, at a minimum, greedy; however the Rays have been able to add roughly two wins by being aggressive on the bases.

In the majors, Tampa Bay ranks only eleventh in stolen bases (63), but on the whole, there’s no team better at baserunning.