SAN FRANCISCO -- It's the proverbial gut check time for the Chicago Cubs as they'll likely be without their emerging star catcher for a while. Willson Contreras will have an MRI on his right hamstring on Thursday, but no one who saw him come up lame running to first base on Wednesday afternoon believes it's a one- or two-day thing.

It's not hard to understand how big of a loss this could be for the Cubs, who find themselves in a four-team race for the division title. Contreras has been Chicago's MVP of late.

"Any kind of offensive resurgence we've had has primarily been centered around him and his contributions," manager Joe Maddon said after the injury. "As bad as it seems on the surface, it could galvanize the group. They know that he's not here, and now other guys realize, 'Let's go, we have to pick up the slack.'"

By that logic, the Cubs are two injuries away from winning it all again. But Maddon's sentiment is still right on the money. It's time for the club's offense to be dangerous again ... not just at the top of the lineup, but throughout. It might help if their defense could play a bit better, too. Shortstop Addison Russell is sidelined with a foot injury, so the Cubs have some holes up the middle. It means Javier Baez, Ben Zobrist and Ian Happ need to do their part -- on both sides of the ball.

"We have not played with the same kind of efficiency that we had been playing with coming out of the break," Maddon said. "We have to push ourselves mentally, more than anything, to get over the hump."

Now more than ever the Cubs need to push because their schedule is about to get a lot lighter. They easily overcame a yearlong injury to Kyle Schwarber last season, and that wherewithal will be needed again, as Contreras was turning into the heart and soul of the team. Now he'll most likely be a cheerleader from the dugout for a few weeks -- leaving a void to be filled on the field.

"He's been very productive the last couple of months and a huge part of our order," backup catcher Alex Avila said. "We have to pick up the slack."

All of a sudden, the move to pick up Avila at the trade deadline -- instead of just a warm body like A.J. Ellis -- is looking better and better for the Cubs' front office. Avila had an .869 OPS before the deal, and he has thrown out 31 percent of would-be base stealers. That's a higher percentage than Contreras.

"The biggest thing with Alex is Jonny Lester," Maddon said. "The involvement with a new catcher with Jon. I have a lot of faith [in him.] There's a lot to like."

Avila added: "I've caught most of the guys already. It usually doesn't take me too long to feel pretty comfortable with a pitcher back there."

A quick learning curve for Avila, better infield defense up the middle, and a more diversified offense should be the Cubs' wish list right now after their series loss in San Francisco. Is that too much to ask for a team that's rarely played all facets of the game in a positive manner this season? We're about to find out. The loss of Contreras will test the defending champions in a big way. Unlike with earlier injuries, they'll have less time to overcome this injury and less margin for error.

"We have to keep playing baseball," Anthony Rizzo said. "It's upsetting for him and for us too."