With reliever Dan Cortes placed on the 15-day disabled list in order to create a roster spot for Vasquez, the bullpen currently is at six and could stay there until rosters are allowed to expand with September callups, Wedge said prior to Wednesday's series finale in Cleveland.
"What we need to do is kind of take it day to day to get to September and then go from there," said Wedge.
Wedge and pitching coach Carl Willis have talked about going to a six-man rotation for a while now as a way to ease the workload on 22-year-old rookie Michael Pineda and others.
Felix Hernandez, who had already thrown 194 1/3 innings entering Wednesday's start against the Indians, is on pace to finish close to last year's American League-leading 249 2/3 innings.
Jason Vargas is on pace to throw 205 innings. He set a career high last year at 192 2/3. The Mariners have eased Pineda's load recently, but he has already thrown 147 innings and is on pace for 186.
"We still have some off-days, so we'll pick and choose how we want to handle these guys," Wedge said. "Obviously, everybody is well aware of Pineda. We have some other young pitchers. And even Felix."
The Mariners went with a five-man rotation with a six-man bullpen for much of the first half of the season, but at that point, they were getting consistent, lengthy starts from their rotation and strong relief from veterans Jamey Wright, Aaron Laffey and David Pauley.
Pauley was traded to the Tigers last month, Laffey has been released and Wright has struggled of late, while the starting rotation has also become less consistent in innings produced, with the addition of rookies Charlie Furbush, Blake Beavan and now possibly Vasquez.
Even with Cortes going on the disabled list, three of the remaining six relievers -- Chance Ruffin, Josh Lueke and Tom Wilhelmsen -- are rookies.
"Different situation," Wedge said of going with a six-man bullpen at this point. "We're going to take it day to day. We're a little thin today. Hopefully, Felix [Hernandez] has a good day for us. But we'll take it day to day, and hopefully in September, we can add a couple guys."