CHICAGO -- The Cubs simply have no way of projecting right now how much of an impact José Quintana will have on the upcoming season. All the team knows at the moment is that the lefty took a step forward on Thursday morning.

"It's a big wait and see," said Cubs manager David Ross.

Quintana played catch on flat ground from a distance of 60 feet on Thursday at Wrigley Field after having stitches removed from his left thumb on Wednesday. Quintana sustained a laceration on the thumb while washing dishes at home in Miami and had surgery to repair the digital sensory nerve on July 2.

That setback just before Summer Camp caused a ripple effect on Chicago's rotation. Tyler Chatwood was already a front-runner for a starting job, but the hole open after Quintana's injury locked him into a rotation role. Righty Alec Mills, who had been ticketed for swingman duties, is now in the driver's seat for the No. 5 spot.

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Quintana will continue to build up through a throwing program, but general manager Jed Hoyer said it is far too early to know how the pitcher's hand will respond. The nature of the injury makes things hard to evaluate in the early stage of the return-to-throw process.

"He's such a competitor and he's going to do every right thing to get back," Hoyer said. "But at some point, it's going to come down to how well he feels the ball. Throwing today is not a good way to assess that, right? We're probably not going to have a feel for that until he gets off a mound and is throwing all his pitches.

"The margin for error pitching in a Major League game is really small, so I think we won't find out just how he feels, as far as that sensory part of his thumb, probably until he gets much further along in his rehab."

Rizzo keeps tracking
Cubs first baseman Anthony Rizzo (lower back tightness) had a bat in hand for much of Thursday morning's workout, but he fought the temptation to swing. Instead, Rizzo stood in the box and tracked some live offerings from righties Duane Underwood Jr. and Dan Winkler.

"I don't question Anthony's pain tolerance or willingness to be out there," Ross said. "We'll continue to communicate and make sure he's feeling good and feeling like he can do what needs to be done on the field. If not, we'll take our time with it."

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During Thursday's workout, Rizzo stood in for five "at-bats," tracking 18 pitches, including six that he bunted. Hoyer said it was uncertain whether there was enough time left in Summer Camp for Rizzo to be ready for Opening Day.

"He's losing valuable preparation time," the GM said. "I think tracking is great, but obviously his teammates have had a lot more at-bats. And then you also run into the question [that] we start the season with a lot of games in a row, and so there's going to probably some catch-up he has to do.

"That said, we've dealt with this before. Certainly, our hope at this point is that he can be in there, but I think it's unclear at this point. And you can't rush it."

Worth noting
• The Cubs signed veteran catcher Jose Lobaton to a Minor League deal on Tuesday and assigned him to the South Bend, Ind., alternate training site. Hoyer explained that part of the thinking was that a catcher must be included in the three-man taxi squad on road trips this season, and Chicago felt more depth was needed under the circumstances.

"Especially if we wind up carrying three catchers into the season," Hoyer said, "that means that at times four catchers would be with the team. Because that rule, there's not wiggle room for the taxi-squad person."

• Ross made Thursday's workout a light day for his team, which has been playing regular instrasquad games since the outset of Summer Camp. The bulk of Chicago's regulars had the day off. Chicago will resume intrasquad action on Friday night.

"I thought that was a great job by Rossy, realizing that we've pushed guys hard," Hoyer said. "You have to give guys breaks, and you have to realize that getting guys worn down both mentally and physically is just going to lead to injuries."

• In addition to Lobatón, the Cubs added Cory Abbott and Tyson Miller -- both right-handers on their Top 30 Prospects list -- to the South Bend group, bringing Chicago's 60-man player pool up to 57.

Quotable
"It is a 60-game season and every game is worth 2.7 times more than usual, but you also can't act as though it's a sprint and rush people back from injuries or push guys too hard. You have to realize that you're asking a lot of guys to go from a shortened Spring Training into 17 games in a row to start the season." -- Hoyer