This is precisely why this forum exists!
I've gotten a number of questions/comments about this trade already, so I'll provide a quick view into our thinking.
Cha Seung Baek is a 6'4", 225 lb, 28-year old (turns 29 tomorrow) RHP from Pusan, Korea. Over the past three seasons in the Majors Baek has made 30 appearances, 19 starts, and compiled a 4.84 ERA: 137.2 innings, 141 hits, 40 walks, and 87 strikeouts. Over that same period in AAA, Baek pitched in 30 games, all starts, compiling a 3.03 ERA: 178 innings, 166 hits, 47 walks, and 121 strikeouts.
We've been keeping tabs on Baek dating back to late last year, as we do with all players who will be out of minor league options in the coming season. In this particular case, we also knew (as did everyone) that the Mariners had a very deep pitching staff, and that Baek would be fighting for a spot on the team. When the Mariners acquired Bedard, we inquired about Baek again, but the Mariners really wanted to keep him. Fortunately, we saw a lot of Baek during spring training (we share a spring training complex with the Mariners in Peoria, AZ), and our scout, Bill Bryk, really liked him and recommended that we continue our attempts to acquire him. Nevertheless, we couldn't work out a deal, and Baek opened the season on Seattle's roster.
We believe Baek is a very good strike-thrower with all of his pitches (Fastball, Curveball, Slider, and Change), which keeps hitters off balance and makes him effective. Our scouts also believe that he pitched a little better than his ERA would indicate from last year. According to the FIP statistic, a defense-independant statistic developed by Tom Tango and utilized by The Hardball Times, Baek had been getting better in each of his past three ML seasons (2004-2007), which goes hand-in-hand with our scouting evaluations.
Jared Wells is a 6'4", 200 lb 26-year old RHP from Texas whom the Padres drafted in the 31st round in 2002. Jared made his first Major League appearance just this past week for the Padres. After moving up through the minors as a starting pitcher, Jared made the transition to the bullpen in the middle of the 2007 season while at AAA. Jared pitched well in that role, particularly against right-handed hitters.
Jared will be out of options next season, meaning that he has to be on the Major League roster for the entire year or be placed on outright waivers. Though we like Jared quite a bit, there were three elements in play: 1) given our current injuries, the need for immediate help at the Major League level, 2) the impending lack of roster flexibility with Jared, and 3) our other internal bullpen options going forward. Those three elements combined helped us to make this deal. It's not as though we don't think Jared Wells is a good pitcher - we do. Remember, when you make trades, you have to give up something of value - you don't get something for nothing.
In comparing Baek and Wells, though, we believe Baek has the chance to be a starting pitcher. That was the separator for us and made us willing to accept his immediate lack of roster flexibility. Will he be a starter for us? I guess we'll all find out together. The bottom line is that there is a chance ("So you're telling me there's a chance..."). Even if he isn't, we expect him to be a solid contributor for the Padres starting now.
One last word as it relates to "designated for assignment". One of the comments stated that this indicated a team's willingness to dump a player for virtually nothing. It's actually the opposite. When a team places a player on outright waivers, any club can claim that player for a mere $20,000. However, when a club believes that a player has more value than that, they will designate him assignment. This designation gives the club roughly a week to trade the player and get something in return that is better than the $20k. If there are no takers, the club will then place the player on outright waivers.