Chicago Cubs starting pitcher Marcus Stroman left the London Series with what seemed like a minor injury, though a mysterious one.

Marcus Stroman has garnered plenty of trade interest over the past few weeks, but if he continues to pitch like the ace he is, then perhaps the Cubs will keep him after all. It helps, of course, that Chicago has been on fire of late. Even Tom Ricketts said the team might not sell, after all.

Against the Cardinals on Sunday, all was fine for Stro until he was seen shaking his hand several times during the fourth inning. Chicago appeared to pull him as a precaution, though at this time it's unclear how serious the injury is.

Cubs: How serious is Marcus Stroman's injury?

Chicago's pitching staff is finally operating at near-full strength after the return of Justin Steele. As Jordan Campbell of Cubbies Crip explains, any injury to Stroman right now would be deflating to the fanbase.

"The Cubs' pitching staff took a blow on Saturday when it was revealed that both Codi Heuer and Brandon Hughes would not be returning this season as each underwent season-ending surgery.

A major injury to Stroman would have been devastating as with the return of Justin Steele from the injured list two weeks ago, the Cubs had finally been operating with their projected starting rotation fully healthy."

Chicago won its first London Series game over St. Louis handily, as the offense figured out Adam Wainwright and the Cubs pitching staff handled a talented Cards lineup. On Sunday, they were out to a 4-0 lead until the pesky St. Louis ball-club make a comeback.

Stroman's injury is far more important than the result of one game, of course. His health could very well determine the Cubs long-term gameplan as it pertains to the trade deadline and more.