Take lefties Joe Paterson and Mike Zagurski out of the D- backs' pen and you're looking at the second-best relief staff in the National League. Leave them in it, and the D- backs have the third-worst pen in the NL.

Paterson and Zagurski -- the two left-handed specialists that the D-backs have tried this season -- sport 37.13 and 15.43 ERAs, respectively. They're responsible for nearly half the runs and home runs that D-backs' relievers have given up as a group. Paterson was optioned to Reno on April 24 and Zagurski isn't exactly giving himself a foothold in the big leagues.

Nevertheless, here are the bullpen numbers that I was going to present, I'll just save you the corresponding commentary:

• 4.66 ERA -- third-worst in the NL

• Five losses -- second-worst in the NL

• 10 home runs -- worst in the NL

• .456 opponent slugging percentage and .787 opponent on-base-plus-slugging percentage -- both worst in the NL

With some longer, more quality starts, like the one Joe Saunders had last Friday, and the addition of a solid veteran like Takashi Saito, the D-backs' bullpen should rebound to pitch to its former and expected caliber.

April in hindsight

The D-backs finished the month of April above .500 for the first time since 2008. Their 12-11 record won them three series and lost them four, leaving them in third place in the NL West -- four games behind the Dodgers.

Chris Young has now been on the disabled list for more than half of the D-backs' games with the right shoulder contusion he sustained from crashing into Chase Field's center field wall. At the time of his injury, he was one of the hottest hitters in baseball -- trailing only Matt Kemp in home runs, RBIs, batting average, and OPS.

Daniel Hudson -- the fifth-hardest thrower among NL starters this season -- is also on the disabled list with right shoulder problems, except his has an impingement.

Bear in mind the recoveries of shortstop Stephen Drew and the aforementioned Saito, along with the multiple games Justin Upton and the 60-day disabled list status of utility man Geoff Blum, and D-backs fans could make some awfully positive "all things considered" statements about their team. Indeed, the team has played quite well, despite some extremely costly injuries.

Injuries aside, key bats like those of Justin Upton (.242 AVG; 5 RBIs), Paul Goldschmidt (.193 AVG; 1 HR), and Ryan Roberts (.152; AVG .240 OBP) were largely underwhelming in April.

May in foresight

Of the 10 series -- including two two-game series -- that the D-backs have scheduled for May, eight are against teams that have records of .500 or greater. They face both the Giants and Dodgers twice and the Rockies once. They'll also see the defending Word Series champion Cardinals and the historically-bad Royals.

With such a flurry of difficult matchups ahead, injury recovery time will be crucial.

May was a good month to the D-backs last year. A really good month, in fact. The team started their unbelievable win explosion on May 14 last year and finished the month with a 19-10 record -- going 15-3 in their final 18 games of the month. Such a spurt will be a lot more difficult to pull off this year, given the schedule and injury situations but, again, the month is critical to the D-backs' success, with five divisional series matchups on the schedule.

The pitching rotation will likely undergo some transformation by the time May is coming to a close. After Josh Collmenter's significant struggles were overshadowed by Wade Miley's tremendous success and Patrick Corbin's solid debut, the D-backs enter the month with three southpaws in the rotation. Also, three of their starting five are 25 or younger. There's no telling how things in the D-backs' rotation will have shaken out 31 days from now, given Hudson's recovery and Miley and Corbin's relative inexperience.

Upton, Goldschmidt, and Roberts (mentioned above) will be vital to an upswing in the D-backs' offense. Cody Ransom can't be depended on for production for much longer.