HOUSTON -- Cubs left-hander Mike Montgomery jogged to the mound in the bottom of the fifth inning in Monday's 6-5 loss to the Astros knowing he would not pitch. Near the end of his warmup, his left middle finger developed swelling and numbness.

By then, there was no time for manager Joe Maddon to get another reliever up, so Montgomery took the mound and was then escorted back to the dugout by the team’s medical staff as reliever Kyle Ryan entered the game.

“At that point, you don’t know what it could be,” Montgomery said. “It could be the ligament in there. At the end of the day, I couldn’t feel the ball, so I knew at that point I wasn’t going to be able to pitch. It looks like a popped blood vessel or something.”

“It’s not sounding horrible right now,” Maddon said of Montgomery. “We’ll see what that looks like tomorrow."

Montgomery missed more than a month this season with a mild left lat strain, returning from the 10-day injured list on May 8. He’s hopeful he might be available as early as Tuesday.

“They said it could be gone for tomorrow,” Montgomery said. “It’s still tender. The tip of your finger is such a sensitive spot. Hopefully, the swelling stays down and the tenderness goes away. It was one of those things where I wasn’t going to be doing us any favors by trying to pitch through that.

“I’ve never had anything like that before. Never had any blister problems. I just knew it was swollen and numb like someone hit it with a hammer. It was one of those freak things. I think it was just a freak deal. It just happened to be two minutes before I was coming in the game.”

The Cubs trimmed their relief staff from nine to eight on Monday, sending lefty Tim Collins back to Triple-A Iowa. The Cubs are coming to the end of a stretch of 26 games in 27 days. Closer Pedro Strop is scheduled to make a rehab assignment Tuesday in New Orleans and could be activated for this weekend’s series in St. Louis.