The teams will be swapping shortstops at the Major League level, with the Mariners sending over Ronny Cedeno as part of the deal. The Pirates also sent right-handed starter Ian Snell.
The package the Mariners sent to Pittsburgh included C/1B Jeff Clement and three A-ball pitchers: Brett Lorin, Nathan Adcock and Aaron Pribanic.
Pittsburgh is paying all but $400,000 of the remaining salaries of Wilson and Snell for the remainder of the season.
Let's take a look at the players involved in the deal.
The centerpiece of this deal for the Mariners, Jack Wilson is a flashy defensive shortstop. Pirates fans have enjoyed watching him make several beautiful plays over the years, and he's had his share of rotations in ESPN's Web Gems.
Statistically speaking, he's in the middle of the best defensive season of his career.
The big knock on Wilson is that he can't hit to save his life. Of course, neither could anyone else the Mariners were playing at shortstop. The addition of Wilson will help stabilize the team's middle infield defense, which has been a weakness for them all year.
The 31-year-old Wilson is likely no more than a one-year rental for the Mariners, who have the ability to buy out of his option next year for $600,000 if they don't feel he's worth keeping on board.
Snell had a full season's worth of dominant baseball in Pittsburgh split over two seasons, and he may make an interesting reclamation project for Seattle. However, he had burned his bridges in Pittsburgh.
At 27 years old, Snell still has some potential to be wrung out of him. He has amazing stuff, with lots of zip and movement to all of his pitches.
The knock on Snell is a mental one. Although he has the tools to succeed, at times he gets into mental blocks on the mounds and serves up fat pitches to the outer part of the plate.
Pitching coaches and fans alike have criticized his steadfast refusal to spread the ball around the zone, preferring to constantly work the outer half of the plate.
Snell has a reputation for his temper. While Pittsburgh reporters have denied it, fans have gleaned from the quotes in the papers that he has a tendency to fly into fits of rage when things don't go well for him on the mound.
This year, Snell requested and received a demotion to AAA, and while there revealed to the Indianapolis media that he had been struggling with depression and contemplating suicide. Perhaps the change of scenery in Seattle will help him get his life back on track.
A utility infielder that will likely start at shortstop for Pittsburgh with Wilson gone.
Cedeno is below average both offensively and defensively. He's been the backup middle infielder for both the Cubs and the Mariners, and he plays a better defensive second base than he does shortstop.
There will be a tendency among Pirates fans to focus on Cedeno as the centerpiece of this deal, as he's the only player that will be assigned to the Major Leagues right away, but that's a fallacy.
Cedeno is by far the least important player in this deal and was likely acquired only to be a stopgap. In that role, he's probably better than Brian Bixler, but not much else can be said about him. Except him to be displaced some time next year.
The actual center piece of this deal, Clement is a C/1B with significant upside. He alone could make this deal worth it for the Pirates, and I'm shocked the Mariners included him in the package.
Clement was ranked Seattle's No. 1 prospect in 2006 and 2008 by Baseball America, and was highly ranked this year as well.
Clement was Seattle's backup catcher behind Kenji Johjima. The team had him play primarily at DH during his two short stints in the Majors. He was optioned to AAA this year.
At 25 years old, Clement has put together strong offensive minor league numbers for his entire career. He keeps his strike outs low, walks a bit more than the average player, and has the ability to hit for power.
His line in AAA since being optioned is .288/.366/.505 with 14 home runs. It's worth noting that Clement plays in the hitter-friendly Pacific Coast League, but it's also worth noting that the Mariners AAA affiliate has a very pitcher-friendly home ball park.
It's unlikely that he'll remain in AAA for much longer in the Pirates organization, as he's not blocked by anybody.
For the time being, Clement is more likely to play first base than catcher when called up, as Ryan Doumit is an above-average catcher that Pittsburgh is probably going to try to trade next season.
The question is where Clement will remain. Even if Doumit is traded, the Pirates have another above-average catcher in Jason Jaramillo, and they drafted Boston College catcher Tony Sanchez with their first selection this year and have him on the fast-track to reach the Majors.
Both play much better defense than Clement, which Pittsburgh values from their catchers.
There's also the issue of Clement's knees, which are known to be bad. This could preclude a move to first for him, but the Pirates also kept injury-prone Ryan Doumit at catcher, so who knows?
Many people also believe that Pedro Alvarez will move from third to first base as a Major Leaguer. It's possible that the Pirates truly see Alvarez as a third baseman, which would sort everything else out naturally.
At the time being, both the Pittsburgh Post-Gazette and the Pirates' official web site list Clement as a first baseman, but I find it hard to believe the Pirates won't give him any kind of look at catcher as well.
Currently in his second year of professional ball in low A, Lorin was the Mariners' fifth round draft pick in 2008. He is 6'7", giving him a nice projectible frame.
Lorin has been dominant in low A so far, striking out 87 batters and walking 25 in 88.2 innings. He has an ERA of 2.44 and a WHIP of 0.97.
At age 22, Lorin is a little old for the level he's pitching at, but again, it's his second year since being drafted out of college. He'll likely move to high A relatively soon in the Pirates system and start next year at AA.
A 21-year-old pitcher in high A, drafted out of high school in 2006. Another fifth round pick.
His DIPS are nothing to be impressed with. He has 71 strike outs compared with 54 walks in 102 innings this year, and he seems to have a problem with giving up the long ball.
The least likely of the pitchers to make a Major League impact judging by stats. Adcock is a fringe prospect, and his ceiling is likely as a reliever.
Another 22-year-old in low A, drafted in the same class as Lorin in the third round.
Not a strike out pitcher, Pribanic is never the less a decent looking borderline prospect. He doesn't walk many batters, and is an extreme ground ball pitcher. He has only surrendered one home run in 87 innings.
It's difficult to project his ceiling right now, but it looks like he could be either a back-end starter or a middle reliever. The ability to limit the damage and keep the ball on the ground will keep him from taxing his arm too much, and that's valuable in its own right.
A good deal for both sides.
The Pirates got way more than I would have ever dreamed of for Jack Wilson and Ian Snell here, which makes me think the Mariners overpaid.
Meanwhile, the Mariners got a shortstop that will shore up one of the weakest areas of their team, as well as a nice reclamation project.