Statcast of the Day: Diaz runs wild on Lester

Big leads may inspire more steal attempts against Cubs' ace

Statcast of the Day: Diaz runs wild on Lester

Each of Jon Lester's starts in the 2016 postseason shared a consistent storyline: Would baserunners try to steal on him?

Lester, along with his accolades and World Series titles, had gained a reputation over the years for his refusal to throw to first base. That hesitance was magnified even more under the bright lights of the Cubs' storybook postseason run last fall, but with personal catcher David Ross behind the plate, opponents were flummoxed, as they couldn't find ways to consistently steal bases off Lester -- even as they took massive leads.

Statcast: Dodgers' baserunning

Baserunners were a focus for Lester once again in the Cardinals' 4-3 walk-off victory in Sunday night's season opener. With Ross, now retired, cutting a rug on ABC's "Dancing With the Stars," fans and opponents alike got their first chance to see Chicago's new battery of Lester and second-year catcher Willson Contreras. Cardinals shortstop Aledmys Diaz took full advantage of the new pairing to steal a pair of bases and, at the same time, create a potential blueprint for how opponents can make Chicago's lefty ace more vulnerable.

Diaz singled in the bottom of the third, then stretched out a 25.2-foot secondary lead off first base, as measured by Statcast™, before taking off for second with one out. Diaz's lead was five feet larger than the average secondary lead that baserunners have taken against southpaws on successful steals of second over the first two seasons of the Statcast™ Era, and he stole second without a throw from Contreras.

For context, secondary lead is the runner's lead as measured when the pitcher releases the ball, as opposed to primary lead, which measures his lead at the pitcher's first movement toward home.

Diaz stole just four bases as a rookie last season, but he decided to test Contreras again one at-bat later by stepping out for a secondary lead of 33.6 feet before taking off for third. Once again, Diaz's secondary lead was five feet larger than the MLB average for runners on steals of third base. That massive lead left Diaz with less than 60 feet of ground to cover, and he slid into third well ahead of Contreras' throw.

"That's something that we talked about before -- it's hard when you tell a guy to do that, and you get out there and you feel like you're in no-man's land, especially when you get to second base and you have everybody playing back," Cardinals manager Mike Matheny said of Diaz's aggressive leads. "Really, with two outs in that situation, sometimes it's not a great play [to steal third] except [that] we might have to scratch and claw and look for a ball in the dirt that we might be able to score on or an infield hit. It was smart. He knew the odds and felt really good about it, so we let him go."

Although Diaz made quick of work of getting from first to third, the Cardinals' offense stranded him there, and Lester, as he did last postseason, escaped a tricky situation on the bases. But the ease with which Diaz ran against the southpaw highlighted a dynamic between Lester and Contreras that will be worth keeping an eye on throughout the season.

Contreras averaged 86 mph on "max effort" throws (or throws at or above his 90th percentile) in his rookie 2016 season -- the third-highest average of any qualified catcher behind the Padres' Christian Bethancourt and the Yankees' Gary Sanchez -- while Ross clocked in nearly seven mph slower, at 79.2. The average pop times for the pair (1.95 for Ross, 1.98 for Contreras) were nearly the same.

The biggest difference between the two backstops, in Lester's view, may simply be comfort. Ross threw out 13 baserunners trying to steal off Lester last season, which helped the southpaw concentrate on hitters and post a stellar 2.44 ERA. As he and Contreras adjust to their new arrangement, holding baserunners may continue to be a theme of Lester's starts in 2017 -- thanks in part to the precedent set by Diaz on Sunday night.

Matt Kelly is a reporter for MLB.com based in New York. Follow him on Twitter at @mattkellyMLB. This story was not subject to the approval of Major League Baseball or its clubs.