His longest outing for the Dodgers this year is three innings.
"It's a Sunday day game in Wrigley. What's not exciting about that? I always love pitching here," said the 39-year-old Wright. "I wish I could throw 120 pitches like I used to. Clearly, that's not going to happen.
"I'll go out and have some fun and hope they score 14 runs for me like they did for [Clayton] Kershaw [on Friday]. I'll go as hard as I can as long as I can. How well I do will dictate how long I stay out there. Donnie knows I'll do whatever he wants me to do. I'll start tomorrow and Monday if he wants me to."
Wright got the call over Carlos Frias, who started Wednesday in Colorado in a record-setting outing of eight runs allowed on 10 hits in two-thirds of an inning. Frias also pitched six scoreless innings at home against Washington on Sept. 3, which Mattingly said was a better setup for him.
"His start against the Nationals was the right start," Mattingly said before Saturday's game. "Everybody got excited, but it was a quick turnaround, nobody knows him. In Colorado, anything can happen. He had issues catching his breath, with his hydration. Sometimes it's already in their heads pitching there.
"As of right now, where we're at, it seems the bullpen is the best place right now. For this club, he's a long guy who can give us a couple innings in the middle."
Frias pitched one-third of an inning Saturday, logging a strikeout.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.