With fourth spot Wells set, will there be a Silva lining?

Figuring out the Cubs’ starting rotation has been as easy as 1-2-3 in the early days of the Cactus League season.

Now it’s looking more and more likely you can add “4” to that.

In other words, there’s been very little drama at the top end of the rotation. Those spots are set with right-handers Ryan Dempster, Carlos Zambrano and Matt Garza.

And after Randy Wells pitched shutout ball last week to keep his spring ERA at 0.00, it looks like he’s moving closer to keeping his spot.

Now, all that remains is to see how “5” shakes out.

Carlos Silva provided most of the drama there, at first saying he shouldn’t have to compete for a job and then getting into a dugout dustup with teammate Aramis Ramirez after some poor Cubs defense extended an inning of work for Silva.

Hard-throwing Andrew Cashner now seems to be coming on fast.

So let’s toss the rosin bag into the mound and get to the rotation.

How good is it?The Cubs#146; starting rotation isn#146;t up there with the Phillies #8212; but whose is? The 1-2-3 trio of Dempster, Zambrano and Garza can carry the Cubs#146; for stretches. Does Wells get a bad rap?Maybe so. After going 12-10 with a 3.05 ERA and hearing rookie of the year talk in 2009, Wells fell back to 8-14 with a 4.26 ERA. One statistical site, fangraphs.com, pointed out that Wells#146; combined numbers over the past two seasons compare favorably with those of Garza. Wells did allow a .280 batting average to right-handed batters, who hit 15 of the 19 homers Wells yielded a year ago. For his part, Wells blamed no one but himself for last year#146;s dip, saying he lacked concentration at times. It#146;s also fair to remember that despite being 28 years old, Wells has only 365 innings worth of big-league experience.Who gets the fifth?This one could go to the end of spring training. Silva#146;s numbers are not good, but manager Mike Quade said he#146;d give the veteran the benefit of the doubt. A report also surfaced that scouts from other teams are looking closely at Silva.Nonroster veterans Braden Looper and Todd Wellemeyer are in camp and will get long looks.Of course, the name everybody is talking about is right-hander Cashner, he of the 100-mph fastball. A former closer in college, Cashner was the Cubs#146; first-round pick in 2008, and he has moved fast.The Cubs needed bullpen help in May, so they took Cashner out of the rotation at Class AAA Iowa and put him in the bullpen. After hitting some summertime bumps, Cashner finished strong, and the Cubs wanted to get him stretched out to start.It#146;s not out of the question Cashner could pitch out of the pen this year, but if he can develop more than two pitches, the Cubs see him as a future starter. What about rest of the kids?There are plenty of them, which means at the very least that the rotation at Class AAA Iowa could be an all-prospect rotation to start the season. Or one of these kids could sneak into the big-league picture.Casey Coleman, a protégé of Greg Maddux, was impressive at the end of last season, going 3-1 with a 2.81 ERA in September-October. He fields his position well and can hit and bunt. Others in the mix are lefty James Russell and righties Chris Carpenter, Thomas Diamond and Jay Jackson. Will the lack of a lefty hurt?Against some lineups, Quade will wish he had a lefty going if Russell isn#146;t there. But there#146;s no reason an all-right-handed rotation can#146;t be effective. Who#146;s the hottest prospect?That would be Trey McNutt, a 32nd-round draft pick whom some observers feel has first-round stuff. The 6-foot-4, 205-pound McNutt has moved quickly up the system since being drafted in 2009. In three minor-league stops last year, he went a combined 10-1 with 2.48 ERA. Since turning pro, he has walked 52 and struck out 160 in 144 innings.BBN28642304Carlos Zambrano has had his highs and lows during his Cubs career.Associated PressBBNBBO34003939Associated PressCarlos Silva has endured a rocky spring training in his bid to secure the fifth spot in the Cubs’ starting rotation. BBOBBN17062182Matt Garza joined the Cubs during an off-season trade with the Tampa Bay Rays.Associated PressBBNBBO21372900Andrew Cashner has rocketed through the Cubs’ minor-league system and is making a serious bid at earning the fifth spot in the starting rotation.Associated PressBBO