The Blue Jays, at 51-51 and contending for the AL wild-card spot, pulled outfielder Travis Snider in the sixth inning of a 4-1 loss at Seattle.
Soon thereafter, Toronto announced he was going to the contending Pirates.
"Definitely a shock," Snider said. "With the trade deadline coming up, you never know if it's going to be you."
The Blue Jays acquired Delabar for outfielder Eric Thames.
Teams have until Tuesday afternoon to make deals without waivers.
Snider went 1 for 2 with a walk in his final game for Toronto. The 24-year-old began the day batting .235 with three home runs and eight RBIs in nine games for the Blue Jays. He hit .335 with 13 homers and 57 RBIs in Triple-A this year.
The right-handed Lincoln was 4-2 with one save and a 2.73 ERA. The 27-year-old pitched 28 games for Pittsburgh this year.
"We're parting ways with a young, talented outfielder in Travis, who has still been trying to get established on an everyday basis in the big leagues," Toronto manager John Farrell said. "We felt like we gave up a quality player to get a guy that has starting to come into his own in Lincoln."
Lincoln has been a starter and reliever during his career.
"We envision him in the bullpen. That's where he's flourished. That's where he seemed to come into his own at the big league level," Farrell said.
Pittsburgh is in playoff contention for the NL Central title and the wild-card spot.
The 29-year-old Delabar is 2-1 with a 4.17 ERA in 34 games for Seattle. In parts of two seasons with the Mariners, he is 3-2 with a 3.92 ERA in 40 games.
The 25-year-old Thames hit .243 with three home runs and 11 RBIs in 46 games for Toronto.Suggest a correction