Jerry Dipoto is up to his old tricks again. The Seattle Mariners GM, who made more trades last winter than any MLB team in the last 20 years, has pulled off trades on back-to-back days as we approach baseball’s trade deadline.

On Thursday, he acquired Miami Marlins reliever David Phelps, who has some solid peripherals, but isn’t exactly the key to a long-lost playoff berth in Seattle. The cost? Four minor leaguers, including Brayan Hernandez, who was Seattle’s No. 6 prospect.

On Friday, Dipoto dealt Seattle’s No. 3 prospect, power-hitting outfielder Tyler O’Neill, to the St. Louis Cardinals. A somewhat surprising move, since O’Neill has hit 75 minor-league homers since the start of the 2015 season. Their return? Marco Gonzales, a 25-year-old pitcher, who has played in parts of three MLB seasons, most notably in 2014. He sports a 5.53 ERA in 10 career appearances and will report to Triple-A, according to Ryan Divish of The Seattle Times.

It’s not uncommon this time of year to see contending teams trade their prospects for proven big leaguers that can get them over the hump and into the postseason. But Seattle’s deals haven’t exactly done either of these things. The Mariners are within striking distance of the wide-open AL wild card, but at 48-49, they’re just as likely to flame out as they are to charge into the postseason. And their return in these trades isn’t exactly earth-shattering.

Which makes us wonder: What the heck are the Mariners doing here?

View photos Mariners GM Jerry Dipoto keeps making trades. (AP) More

To that point, a few thoughts:

• Maybe Dipoto feels the playoff pressure. The Mariners haven’t made the postseason since 2001, the longest such streak in MLB, which puts the pressure on Dipoto to do the best he can when he sees a lane in front of him. The AL West isn’t really that, as the Houston Astros have a 16-game lead on the Mariners. The wild card might be. The Mariners are 2.5 games out of the second wild-card spot. Totally possible. But they’re also one of six teams within five games of the Yankees, who hold that second spot. So lots of traffic in that lane.

• Maybe Dipoto sees something we don’t. After the Phelps trade, the Mariners GM talked about how expensive starting pitching is right now. The Jose Quintana trade proved that. The Mariners need arms, but don’t really have the assets to get a Sonny Gray or Justin Verlander or even a lesser-priced starter. In Phelps, Dipoto sees a reliever who can handle multiple innings or even start one day. What if one day is September? In Gonzalez, the Mariners are getting a pitcher who has been hyped — he’s a former first-round pick — but he’s not atop the list of trade-deadline difference-makers. He’s been sharp in Triple-A this season, with a 2.90 ERA in 11 starts, but that’s a long way from helping the Seattle rotation next week. Unless, of course, Dipoto sees something we don’t.

• Maybe the Mariners soured on O’Neill. It happens, right? While he ranks well on the team’s overall prospect list and fans seemed excited about him, O’Neill didn’t crack Baseball America’s midseason Top 100 list after being No. 38 at season’s start. He has 19 homers and 56 RBIs so far this season in Triple-A, but his batting average is down almost 50 points, from .293 to .244. His on-base percentage took a similar dip. Prospects are always a gamble. So in effect, the Mariners are just gambling on a different one now.

View photos Tyler O’Neill, the Mariners No. 3 prospect, is headed to St. Louis. (AP) More

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