Dipoto said Vincent will take the final spot in the Mariners' bullpen, meaning right-handed candidates Donn Roach, Blake Parker and Mayckol Guaipe will open the year with Triple-A Tacoma.
The Mariners' seven-man bullpen will consist of closer Steve Cishek and fellow right-handers Joaquin Benoit, Tony Zych, Joel Peralta and Vincent, along with lefties Vidal Nuno and Mike Montgomery.
• Zych a key member of Mariners' bullpen
Vincent joined the Mariners immediately on Wednesday, having to just walk across the Peoria Sports Complex the team shares with the Padres, but Dipoto said he wouldn't be asked to pitch in the afternoon's game against his former team.
Vincent, a San Diego native, said he was "still a little in shock" after getting traded by the team that drafted him in the 18th round in 2008, but eager for a chance to help his new team.
"I don't know what my role is going to be here, but I'm going to attack guys," Vincent said. "They call me 'the Bulldog' on the mound because I'm 5-10, 5-11 and 175 pounds. I'm not a big guy, but I'm not afraid of anybody who goes up there. I have the bulldog mentality. Everybody has doubted me my whole career, so that's been the end result."
Vincent has allowed five runs in 8 1/3 innings in nine Cactus League outings this spring and posted a 3.04 ERA with 68 strikeouts in 50 1/3 innings in Triple-A El Paso last season. The Long Beach State product has 161 strikeouts in 150 2/3 innings in his big league career.
"He has really dominated right-handed hitting, and there's no reason to expect that to change," Dipoto said. "He's very cutter-centric and has a very usable fastball. He's got some history in the big leagues, and it gives us a nice upgrade and additional depth in the bullpen. We were looking for that and needed it, based on what happened through the course of this spring. This is a nice solution. And fortunately, he only has to walk across the parking lot to take part."
• Benoit, Nuno named Mariners' setup men
The bullpen took some hits early in camp with injuries sidelining right-handers Evan Scribner and Ryan Cook, while lefty Charlie Furbush won't likely be ready until at least May as he deals with continued soreness in his shoulder.
But Dipoto is not looking to make any further additions before Opening Day on Monday in Texas.
"I feel we have five solid Major League relievers from the right side, and with Nuno and Montgomery, that gives us two lefties -- one with power and one with unique matchup ability vs. lefties," he said. "That's a seven-man bullpen we're pretty comfortable with."
The Mariners' 40-man roster is full with Vincent's addition, so one move will need to be made to open a spot for when Peralta -- a non-roster invitee -- is added by Sunday. One possibility is putting Scribner on the 60-day disabled list, since Dipoto said his recovery from a strained lat remains slow. The club is hoping Furbush can start throwing in about three weeks.
Roach was the likely candidate to earn the final bullpen spot prior to Vincent's acquisition as he's had an outstanding camp and "opened a lot of eyes," according to Dipoto. But he'll now head to Tacoma and resume working as a starter to provide additional depth there.