Let's see what we've got here. Tuiasosopo for Wilson? This is just a move to get us an actual backup shortstop. Tui was primarily seeing time between Figgins and Lopez, and he's booted a few balls and made some bad throws. His unwatchable defense has only enhanced the downside of pinch-hitting for Jack Wilson. Josh Wilson, as we all know, isn't much, but the gap between Tui and Wilson in the field is like the gap between Rob Johnson and a catcher, so he gives Wak an actual option. It doesn't hurt that Wilson's been swinging a good bat in Tacoma, with a .333 average and 12 extra-base hits. Tui'll play regularly in the minors and try to develop into whatever he's going to be. Wilson probably goes away if and when Jack Hannahan demonstrates some competence in the middle infield.
Byrnes for Langerhans? I don't know that 38 plate appearances is proof of Byrnes' uselessness, but he didn't do anything to endear himself to the organization, so his going away comes as little surprise. Langerhans will come up and offer some actual talent and good defense without having to make a whole show of it. The tricky part here is that Langerhans is left-handed, which is difficult to reconcile with the desire to give Griffey regular time at DH, but then, maybe that means the team has gotten sick of Griffey at DH, which would be wonderful. Langerhans is a decent player, and it'll be nice to see him come back. It's also very possible they just stick him on the bench as the fourth OF.
The biggest critique of the moves so far has been that Mike Sweeney isn't involved, but then, I don't know what you expected them to do. They're not just going to cut him outright, and it's not like the system is bursting at the seams with Major League-caliber players. Certainly not right-handed bats. Who do you want? Tommy Everidge? What the M's need to do is put Sweeney on the DL and go outside the organization to fill his spot, and that's not something you can do in a snap. They have tomorrow off. There'll be conversations.
Talent-wise, there's nothing but gain. Blogging-wise, things won't be the same without Byrnes on the roster, but his last act of any significance was storming out of the clubhouse on a bicycle, and for that I say kudos, Eric. American television producers could learn a thing or two out of this.
Update: as Drayer points out, these moves bring the Mariners' 40-man roster to 41. Outside shot you could see someone kicked off the team, I guess, but the likelihood is that it's something minor. Drayer says the next move "will not be a 60 day DL move," but Ricky Orta underwent Tommy John a few weeks ago and isn't yet on the 60-day DL, so, who knows? Orta just seems so obvious. Could also see, I dunno, Varvaro go away, or even a two-for-one trade.