Heading into the year, the Mariners plan seemed to be to acquire as many low-ceiling middling prospects as they could find and throw them all at the wall, hoping one or two would help stabilize the back end of the team’s rotation. Over the last year and change, they’ve acquired and started Ariel Miranda, Dillon Overton, Chase De Jong, Chris Heston, Christian Bergman, and Ryan Weber. Thanks to a .220 BABIP, Miranda’s been a reasonable enough starter for the team, but most of the other guys made a few low-quality appearances and were then shipped back to Triple-A.

But the Mariners are apparently undeterred, and are trying this strategy one more time.

#Mariners acquire LHP Marco Gonzales from St. Louis for minor league OF Tyler O’Neill. — Ryan Divish (@RyanDivish) July 21, 2017

Given that Gonzales was a first round pick back in 2013, he’s a bit less fringy than most of the above group, but he fits the general profile of a lower velocity, pitch-to-contact guy who will likely rely on command to get outs in the Majors. Before the season, Eric Longenhagen hung a 40 FV grade on him in his Cardinals write-up.

Remember Marco Gonzalez? He’s still rookie eligible after making his big-league debut back in 2014 and proceeding to deal with various injuries (including a shoulder issue in 2015, TJ early in 2016) since then. Healthy Gonzalez was 88-92 with tail and life (he’d miss bats up in the zone with that fastball) while featuring a plus changeup in the 76-78 mph range with significant fade, a fringe to average curveball, and flashes of plus command. He was — and, you could still argue, remains — a potential mid-rotation starter. He was missing bats in the spring of 2016 before getting injured. He’s begun throwing again and should be ready to face hitters at some point toward the end of spring training, at which point we’ll see how much of his stuff is there.

Gonzalez has been okay-ish in Triple-A this year, and made one spot start for STL this summer, where his fastball averaged 91, right where it was before the injuries. He looks more like a back-end starter than a mid-rotation guy at this point, but of course, there’s plenty of value in a young cost-controlled starter if he can actually become a reasonable MLB pitcher. As Dipoto said yesterday:

Given the price for arms you can keep around for a while, Gonzales could turn out to be a valuable piece, even if he’s just a fifth starter. But that’s definitely still an if.

To land Gonzalez, the Mariners gave up Tyler O’Neill, who Eric graded as the team’s second-best prospect heading into the year.

A dense pillar of meat, O’Neill — at a shredded 5-foot-10, 210 pounds — is the most muscular baseball player many scouts have ever seen. But unlike most players with similar measurables, O’Neill is an above-average straight-line runner, has good range in (but not great feel for) the outfield, and an above-average arm. He does have the sort of power one might expect from a walking bicep, arguably plus-plus raw, and most scouts think O’Neill’s combination of ball/strike recognition and minimalist swing will allow him to catch enough fastballs to hit 20-plus homers annually despite justifiable questions about the hit tool. Scouts who saw O’Neill in the Fall League noted that he swung through or made sub-optimal contact with lots of hittable pitches in the zone, and they have questions about the hand-eye or bat control. But he should do enough to play every day even if the hit tool ends up below average and, if you just look at the tools and not the unique physique, O’Neill has a pretty standard right-field profile. He projects as an average regular.

Despite catching fire lately, O’Neill has had a disappointing year in Tacoma, running just a 104 wRC+ with a strikeout rate that remains too high. The power still looks legitimate, but he might swing and miss too regularly to live up to Eric’s hopes of an average regular. That said, there’s still pretty clearly some upside here — KATOH had him 13th overall on the stats-only version of its prospect list before the season — and the Cardinals did pretty well to get a potential power bat with some athleticism for an arm who profiles as a swing pitcher with injury history.

But the Mariners have been making win-now moves for a while now, and Gonzales can probably help this team in 2017, while O’Neill was at least a year away. The Mariners clearly are swapping upside for something they see as a lower-risk profile and closer proximity to the Majors. Make enough of these trades and you’re going to end up giving away a star for someone who isn’t any good, and now the Mariners will have to hope Gonzales provides enough short-term value to justify the lost upside.