How many do you keep going forward?
First impression is that if Upton returns to form and Desmond Jennings finally puts it together you've got a nice dynamic power/speed offense comprised of guys who should be able to 20/20 in their sleep (that is, if Desmond Jennings actually has 20/20 power. i personally see him more of a low-mid level steals guy with relative power potential)
I'd definitely try to get a 3rd closer in a 14 team league. I like to have 5-6 in 12 team leagues, but that's mainly because I like getting out to a big fast start in saves while I figure out my SP because if you can hold down the pitching categories that's half of the battle, not to mention being the guy with 5-6 closers going means that you'll be able to make deals from a position of strength after you've gotten out to a saves lead/top-3 that you can hold on to going forward.
Your infield is a bit suspect, as Freddie Freeman is nice and young but needs to take a step forward to ~30/100-dom in order to be an anchor that can make up for some limited production in the IF. phillips had a relatively down year at 2B as you hope for that ~20/20 type greatness that makes him one of the more solid unheralded guys at the position, but if he does another 15/15 season you won't be killed like that. elvis andrus seems to be somewhat of a perennial underachiever; since he's not gonna hit 10+ HRs you really need him to steal ~30-40/+ bases and score runs with a solid average, and last year i think he was only in the 20s in terms of SBs? Seemingly a case of the guy being a more valuable real-life baseball asset as opposed to a fantasy guy. Is Machado potentially a 20+ HR bat at third? There's somewhat of a resurgence of depth at 3B this year after some relatively slim pickings for the last year or two, so I'd prolly be keen to keep an eye out for a potential deal for someone with a ~25/+ HR bat at third if machado doesn't look to be a 3b who can deliver the type of corner power you'll need without having a classic "slugger" type on your team. i haven't had josh reddick on any of my teams but he's on one this year so i'll be interested to see if last year was his "breakout" season establishing a new paradigm of performance in his prime or if it was his "career" year putting up #s he won't approach on an annual basis.
pitching-wise, it's hard to dislike strasburg outside of the injury concerns related to the stress inherent to his pitching motion. Jordan Zimmermann has returned from tommy john surgery nicely with a couple'a good solid seasons in that 150-180 IP range so the hope is that he's able to take the next step and get around ~200IP with a high 2s/low 3s ERA and the WHIP/Ks/wins that come with it. Beyond that your SP takes a dip as I'm not the world's biggest jerrod parker guy, and Ogando, Wandy, and Estrada/MacDonald threaten to pull your ERA up towards 4.00 unless most/all of those guys take a step forward, so i'd definitely be watching out for people who are off to hot starts and roll the dice on them in the hopes of striking gold a la landing Mat Latos in the 2010 season (where he had that magical ~20 start run of 2ER or less, wins be damned)
As for the closer situation, I'd keep an eye on the Angels situation (Madson is supposed to be the guy with Frieri thought to be the heir-apparent guy getting any/all saves in his stead whilst injured... so there's a pretty decent chance that one of those guys is available) and if i'm not mistaken the mets still claim that Frank Francisco is their closer despite a crap year last year, although there's a good chance Parnell (prolly someone who was picked up via the WW after the intiial post-draft waiver period passed) takes the job and runs with it... but that's something to consider. Not to mention the cubs would love to move marmol which means that new japanese closer they signed would step into the role, which makes more sense than Marmol for the cubs.... so I'd keep an eye on that situation too. From there there's always the usual suspects with closing: the pirates, the astros.... maybe even the royals if Holland keeps a WHIP in the high 1.30s and his other peripheral stats start raising up to match that WHIP.
So yeah, I'd definitely be working the waiver wire and look to augment my pitching if those lower level SPs you've got don't pan out. it seems like you got strasburg early and then zimmerman prolly in the ~7-10ish type rounds and then stopped drafting SP for awhile, leading to a dropoff... so definitely be watching who's rattled off 2-3 good starts out of the gate and start riding those guys in the hopes that they have a proper year... you can usually do that with 1-2 pitchers in a given fantasy season, so that's something you'll want to do. also, if there's a pure steals guy out there who's got for-sure playing time out there (everth cabrera, juan pierre, etc) then i'd definitely take a flier on one of them.... cuz while you've got a multi-faceted 5-tool/ish outfield, still, I don't think McCutchen really stole many bases after mid-late May and if Upton is off to a big offensive start with the guys behind him mashing the Braves might not wanna be pushing him to get ~25-30 SB or anything, so I'd definitely wanna look for someone whose whole purpose on your team is to accrue SBs alongside the hybrid power/speed guys you've got. again, andrus is theoretically a steals guy, but when he steps up and hits .280+ with 35+ steals and ~100/+ runs then i'd be comfortable with him. otherwise, yeah, just stay diligent and play the game because i think your team could use a proper masher type.... maybe if you get some good SP performance / pick up a few people and are rolling into may you can take a zimmerman or someone and package him up with a freeman/reddick type and get a more traditional masher. I don't think anyone on your team is a threat for ~40hrs, so without at least one person dedicated to doing that (arguably reddick is but again we've only got one year to look at) i'd want to have that on my squad.
so yeah, stay diligent work the waiver wire augment your SP, get another closer/prospect or two, and if possible see if you can get a big ol power hitter in the ~24-27 year old range, cuz having an OF of power/speed guys is nice and all that but at some point you need someone to mash. if mccutchen starts off real hot and looking like a MVP candidate i might be inclined to deal him for a big return seeing as right now his value is about as high as it'll ever be, that is, unless you think he's in a zen-like state where he'll improve his offense alongside returning to the SB paths, cuz if he does that he's a solid bet for 30/30, but again if memory serves he basically stopped stealing bases in may which left him right at 20... i can also see him dropping from .327 to ~.290-.300, seeing as he was hitting .340-.350 circa late july / early august and he came down to .327.
so yeah good luck with the squad