Tony Snell has no idea when he might play these days, so he prepares as if he's still a part of the Chicago Bulls' rotation.

Snell and Pau Gasol each had 22 points, Derrick Rose added 20 and the Bulls pulled away late for a 104-97 victory over the Toronto Raptors on Monday night.

"I'm staying ready every day," Snell said. "I make sure I'm staying ready at all times."

Snell, who was back in the rotation because Doug McDermott was a late scratch with a sore right knee, had 19 points in the final 17 1/2 minutes — including 16 in the fourth quarter — to spark the Bulls.

If not for McDermott's injury, Snell, who has started 21 games this season, might not have played at all — just like in two of the previous three games.

"I didn't know he wasn't going to play; I had no idea," Snell said of McDermott. "I just make sure to stay ready at all times."

Aaron Brooks had 17 points and rookie Bobby Portis added 12 as the Chicago reserves outscored their counterparts 51-27.

Kyle Lowry had 28 points and DeMar DeRozan added 19 for Toronto.

Jonas Valanciunas had nine points in 20 minutes off the bench after missing 17 games with a broken left hand.

"He's getting his sea legs back, getting the rust off," Raptors coach Dwane Casey said. "He's going to be OK. Jonas is the least of our worries, getting him back in."

Toronto actually got off to a fast start and held the lead for much of the first three quarters.

Luis Scola, who finished with 13 points, had 12 points on 6 of 6 shooting to lead Toronto to a 32-23 lead at the end of the first quarter.

The Bulls rallied in the second behind Brooks and Portis. The two reserves combined to score Chicago's first 19 points of the quarter as the Bulls took a 42-40 lead.

They led by 49-46 before the Raptors scored the last six points of the first half for a 52-49 advantage.

Toronto maintained the lead for most of the third before the Bulls scored the final eight points of the quarter for a 78-73 lead.

"We've got to have some support from our second unit," Casey said.

The Bulls then continued the surge, opening the final quarter with a 13-5 run for a 91-78 lead with just under six minutes to play. Snell had seven points during the run, while Portis added four.

"I'm really happy for Tony," Bulls coach Fred Hoiberg said. "I'm really proud of Tony for staying in there. He's one of those kids that's easy to coach."