Jon Lester isn’t expected to be on the disabled list for long, which of course is great news for the Cubs.

But while he’s there, it’s once again time for Mike Montgomery to audition for a spot in the team’s 2018 starting rotation.

The Cubs are facing the possibility of losing two members of that starting staff this offseason, when both Jake Arrieta and John Lackey will be free agents. Montgomery seems like a logical replacement, but he’ll need to be better than he’s been as a starter this season. He’s put up a 5.13 ERA in eight starts.

He’ll get another opportunity to show his stuff over the next week or so, as he makes one or two spot starts with Lester on the shelf resting up his left lat tightness and general shoulder fatigue.

“I don’t want to see anybody get hurt, especially our ace. But it’s a challenge. I’m looking forward to going out there and helping the team win,” Montgomery said over the weekend. “I’m going to go out there and prepare and be ready to help this team get to the playoffs.”

Montgomery doesn’t have to worry about instilling confidence in his bosses. Joe Maddon and Theo Epstein both lauded Montgomery’s efforts since he was acquired about a year ago, in the middle of the 2016 team’s march to that curse-smashing World Series win. It was Montgomery who earned the save in Game 7.

And again this season Montgomery has given plenty of reason for those guys to have confidence in him. He’s turned in a strong 2.57 ERA in 27 relief appearances, one of the more reliable arms out of what is becoming an increasingly shaky bullpen. This past Thursday, he relieved the early-to-depart Lester, pitching 4.1 shutout innings and allowing just three hits and a walk against the Cincinnati Reds.

Throw in the versatility of being able to effectively switch between starting and relieving, and that’s a recipe for sticking on a big league roster.

“He’s good about bouncing back and forth,” Maddon said. “He’s been invaluable to us the last couple years. He’s still learning his craft. Every time I talk to him it’s kind of like the little lightbulb constantly goes off for him regarding his stuff and how to utilize it. That’s what I’ve been talking about with him the last couple years. This guy’s got all kinds of tools in the toolbox but he doesn’t really know how to utilize them all, and I think he’s finally understanding the cutter, the curve, the changeup to go with the fastball. He’s one of those guys that he should never get wild with his fastball because his pitches are so good and he can throw them for a strike.”

Montgomery’s reliability has been enough that Epstein said there’s no plan for the Cubs to add another starting pitcher before this month’s waiver trade deadline. Of course, the fact that Lester’s injury isn’t as bad as initially feared and the July acquisition of Jose Quintana factors into that, as well.

“We’ve expended a lot of prospect capital trying to make this team better. We think it’s just a start or two (that Lester will miss), and Mike Montgomery is more than capable of filling in,” Epstein said. “He’s thrown the ball really well, like what we saw from him (Thursday). So we’re going to fill that vacancy internally with Mike and go from there.”

While every start made by any pitcher this season seems important — the Cubs entered Monday’s day off with just a two-game lead on the Milwaukee Brewers in the National League Central standings, with a playoff spot hardly guaranteed — Montgomery’s efforts could have just as great an effect on next season. If Arrieta and Lackey both end up departing via free agency, the Cubs will need some replacements. Montgomery figures to be among the first options, especially if this midseason audition goes well.

Of course, Montgomery is happy to do whatever he needs to to help his team. He’s not complaining about a bullpen role or one that has him shuttling between the relief corps and the rotation. But he admitted that starting is his goal, meaning the importance of this moment likely hasn't been lost on him.

“Yeah, absolutely, I wanted to start. But also I wanted to be a guy who could fill another role and hopes that makes our team better,” he said. “If me starting makes us better in their mind, then that’s what I want ideally. But I’ve realized I can’t always control that, I can go out there and pitch well. If I pitch well, they’re probably going to give me more opportunities, which is probably going to lead to starting.

“I think it’s because I spent five years in Triple-A from the time I was 21 and I had a bigger ego. And then you realize that you just want to be in the big leagues and that Triple-A kind of stinks. I think it’s just how I’ve gotten to this point. And coming here last year from a team that was trying to get in the playoffs to a team that was clearly going to win the division, you realize that your role isn’t to come here and start making demands, it’s to come here and just do your job.”

Right now, the Cubs need Montgomery to fill the void while Lester rests up. And if he can make his starts look a little more like his bullpen outings, he’ll do just that. And if that’s what happens, maybe they’ll call on him next season to do a whole lot more.