Chicago Cubs: Is the team asking for too much out of Jon Lester?

The Chicago Cubs boast a presumed strength in their starting rotation. But that could very well be contingent on a 35-year-old, once again, producing as an ace.

Jon Lester has been arguably the best free agent signing in Chicago sports history. We’re four years into Lester’s six-year mega-contract with the Chicago Cubs, and it has become clear the left-hander was worth every penny.

Lester has given the Cubs four years of leadership, production and gutsy playoff performances. The veteran southpaw will undoubtedly get the ball for the Cubs on Opening Day, and is expected to lead the rotation once again.

Rotation outlook

A rotation consisting of a unique blend of veteran hurlers (Kyle Hendricks, Cole Hamels, Jose Quintana, Yu Darvish), all with varying degrees of baggage, will turn to Lester to right the ship in 2019.

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The Cubs starting pitchers will be paid a combined $83.7 million for the upcoming season, and that doesn’t include the $12.5 million owed to Tyler Chatwood.

The Cubs top five starters have all experienced success at a big league level, but the only hurler who would figure to be in the prime of his career entering next season is Hendricks. The Cubs will be taking a big gamble on an aging core of pitchers, with the hope they can continue to produce.

Expectations for Lester

Lester had a phenomenal bounceback campaign from a down year (by his standards) in 2017. Lester finished the year 18-6 with a 3.32 ERA and was an All-Star for the fifth time in his career. However, he did show some signs of regression.

After a sizzling first half of the season, Lester struggled out of the gate after the All-Star Break. He rebounded in September and posted a 4.50 ERA over the second half of the season. While Lester’s second-half performance may have just been a natural regression to the mean, he could have fallen victim to the fatigue that a veteran pitcher faces over the course of a long season.

Lester has also lost significant velocity. During the prime of his career, Lester sat in the mid-90s on his fastball. In 2018, most of the lefty’s fastballs clocked in around 88-92 MPH. As Lester ages, he will become more hittable. According to Statcast, Lester set career-highs in balls barreled and opponent exit velocity in 2018.

It’s once again up to Lester to deliver

Red flags do exist for an individual expected to be the Cubs ace, and the team doesn’t appear to have any succession plan in place. Lester will continue to be someone who will compete and give his team a chance to win every fifth day, but maybe it’s time to stop treating him as a sure ace for the future.

The Cubs farm system doesn’t have many candidates to provide impact to the Major League rotation any time in the near future, which leaves the Cubs in a tough situation if Lester were to experience a significant drop-off in 2019.

For a Cubs team expecting to maintain elite status for some time, an aging rotation doesn’t bode well. While Theo Epstein’s priority is elsewhere during this offseason, the time is coming when the front office will need to acquire young talent to bolster the top of their rotation.