Forget 13-10 Loss, Jon Lester Could Have A Serious Injury

Forget the nine-run, second inning. Forget the 13-10 loss and forget about the series split against the Cincinnati Reds. The Chicago Cubs may a have much bigger problem if the worst case scenario plays out after Jon Lester left Thursday's game with left lat tightness. Lester's day started as well as you could've wished for, retiring the first three batters on six pitches. Then, disaster struck. The Reds scored nine runs in the second inning, seven earned by Lester, who threw 40 pitches and could only record two outs before asking for the trainer and eventually exiting the game.

Jon Lester asks for trainer, leaves game, talks to Bosio in the dugout. Hurt? Pulled himself out? #Cubs pic.twitter.com/K7kQJpFoEo

— Aldo Soto (@AldoSoto21) August 17, 2017

You couldn't really tell what was wrong at the time, but the Cubs later announced Lester departed because of tightness to his lat muscle.

I'm not here to declare all hope is lost for Lester, but here's why a lat injury is devastating for a pitcher. Back in May, New York Mets starting pitcher Noah Syndergaard was diagnosed with a right lat strain and he's been sidelined ever since. Injuries to the latissimus dorsi muscle have also affected several other pitchers including,  Jake Peavy, Roy Halladay, Kerry Wood, Stephen Strasburg, Joe Kelly, Sonny Gray, Brandon Finnegan, Huston Street and Trevor Rosenthal. Lindsay Berra of MLB.com broke down the significance of a lat injury after Syndergaard went on the disabled list three months ago.

So what does the lat do in pitching? Quite a lot, especially if you're a pro. "The best pitchers on the planet use their lats the most," said Eric Cressey of Cressey Performance in Hudson, Mass. "They use big muscles to do big jobs." Cressey also noted that the lat connects the lower body to the upper body to allow for force transfer that ultimately leads to arm speed and ball velocity. "The lat is a powerful anterior stabilizer that works eccentrically to prevent the upper arm from flying off the body in the layback phase of the pitching motion when the shoulder is externally rotated," he said. "The lat then helps to aggressively internally rotate the shoulder during the acceleration phase of the delivery."

After Thursday's defeat, Cubs manager Joe Maddon expressed some worry about Lester.

Lester is going to be examined by a doctor, but there won't be an update for at least another day.

For now, Maddon is trying to stay as positive as he can.

The Cubs are only one game up in the division race, so Cubs fans can only hope for the best when it comes to Lester. Losing him for any extended period of time will make it that much more difficult for the Cubs to hold on to the division. However, this isn't something you like to read about after knowing Lester felt some sort of discomfort in his lat muscle.

The fact that the lat is also a core stabilizer used in basically every human activity as well as a respiratory muscle means it never gets a break, which makes resting it enough to allow it to heal a tricky endeavor. In 2016, a case study done by doctors at the Cleveland Clinic looked at 30 MLB pitchers who had suffered lat or teres major strains. Twenty-nine were treated conservatively and allowed to heal on their own. Only one underwent surgical treatment. The average time required to return to pitching for the non-surgical group was 99.8 days, while the pitcher who had surgery missed 140 days.

The Cubs are already dealing with the absence of catcher Willson Contreras, who won't be back until the middle of September.