Probably won't be enough depending on whether one team in your league has all the elite closers or something. Mike Williams has really been struggling, and you can't expect anything close to last year's save totals. Expect 30 saves or so from him, although if he doesn't pull it together he could lose his spot. Lyon has no job security, and will likely be dumped at the first major implosion. Don't expect more than 15 saves from him.
I think that Politte will be fine as a closer, but he is unproven, and the Jays tend to either lose or really blow their opponents out. Few close games mean few save chances, so don't expect more than around 20 saves. Borowski has been shaky, so Alfonseca will likely get a shot soon, but he has been a shaky closer at best in the past so expect maybe 25-30 more saves between Alfornseca and Borowski, given that the Cubs are a decent team. There is an outside shot that Alfonseca will be dealt to a contender, with Borowski becoming their permanent closer. That would obviously help your save totals, but you can't count on that happening, just consider it a bonus if it does.
Essentially, what you are sorely lacking is an elite closer. In order to be in the top few teams in saves, you need to normally have one elite closer (I'd consider the elite closers to be Gagne, Smoltz, Foulke, Wagner, Percival, Guardado and Benitez), one mid range closer (Williams, Sasaki, Urbina type guys), and a couple of low end closers that you can probably grab from waivers during the season as closer situations clarify. Politte, Borowski, Alfonseca, and Lyon are all low end closers.
Basically, you need to make a deal to acquire a top closer, and then maybe offload two of your low end closers to another team for an offensive upgrade.