The Cubs are 4 games behind the Pirates and have won 5 straight games.

Cubs pitcher Jon Lester is really hot right now and he's also one of those guys who seems to rise to the occasion in big games.
His recent BB/K ratio is spectacular and when contact gets made, it usually results in a ground ball. Chicago is off an impressive road sweep at Milwaukee and underdogs on a winning streak are often very attractive.
I like the Cubs here in this spot as a nice underdog on Monday night.