In Part 1 of this series, we identified five Vikings who will need to improve and/or deliver upon their potential for the team to have any shot at the playoffs in 2012. We continue now with the final five players on the list.

OL Phil Loadholt – Loadholt has had an up-and-down career thus far. He's shown flashes of brilliance as a road-grading run blocker, but has been maddeningly inconsistent in pass protection. The same massive size that allowed him to rank as Pro Football Focus's No. 1 run blocker in the NFL last year also causes problems against quick defensive ends and linebackers. PFF counts nine sacks allowed by Loadholt (only five tackles on either the left or right side allowed more) and a whopping 32 quarterback hurries (among the 15 worst tackles in the league). With Matt Kalil theoretically locking down the left side for the next decade, John Sullivan making big money in the middle, and a number of solid veterans vying for action at the two guard spots, the spotlight will be squarely on Loadholt in his contract year. If he can harness his obvious physical talent and improve his pass blocking, he could be in line for a big-money deal next offseason. It's unclear if the Vikes would be interested in locking him up to a lucrative long-term deal, but they'd love for him to play well enough in 2012 to make it a tough decision.

RB Toby Gerhart – Loadholt's ability to block for the Vikings running backs might be magnified in 2012 if Adrian Peterson is either forced to miss time or isn't back to 100 percent this season. No matter what AP's status is, Gerhart is going to play a big role in the Vikings backfield. Gerhart played very well in two different stints as the main Vikings ballcarrier last year; he scored once and went over 90 yards twice in a three-game span that Peterson missed because of injury in Weeks 12-14, then went over 100 yards on just 11 carries in the calamitous victory over the Redskins in Week 16. We can be sure Gerhart isn't going to single-handedly win games like AP is (or was) capable of doing, but his ability to keep the chains moving will be pivotal to the development of Christian Ponder and the passing game. If Gerhart proves incapable of carrying the load in Peterson's stead, the Vikings have virtually no depth behind him to turn to.

DL/LB Everson Griffen – The former fourth-round pick was viewed as a second-round talent coming out of USC in 2010, and the Vikings thus far have seen both the good (four sacks and frequent quarterback pressure as a part-timer last year) and the bad (a public intoxication arrest in 2011) from Griffen early in his career. The hope is that the off-the-field issues are behind Griffen as he attempts to transition from defensive line to linebacker in 2012. As an undersized edge rusher, Griffen is a bit of a square peg in the round hole of the Vikings' 4-3 defensive alignment, but the ability to rush the passer will play in any scheme. Griffen has obvious physical talents (he was ranked as the No. 3 "prospect" in the NFL in a recent article by Football Outsiders), and if he continues where he left off in 2011 he could become a deadly counterpart to Jared Allen. Harrassing the likes of Aaron Rodgers, Matthew Stafford, and Jay Cutler is obviously of paramount importance in the NFC North, so getting a productive Griffen on the field will be a key challenge for the Vikings defensive coaching staff. Griffen has the makings of a star, but there are still a lot of questions to answer.

TE John Carlson – For distinctly different reason from Chris Cook, Carlson has a lot to prove in 2012 as well. The oft-injured tight end's pressure to perform comes solely as a result of the jaw-dropping five-year, $25 million free agent contract he landed from the Purple at the start of free agency. The addition of Carlson was surprising not only because of the size of the contract, but because of the presence of second-year tight end Kyle Rudolph, who was expected to be one of Christian Ponder's top targets after it became clear the Vikings wouldn't re-sign free agent Visanthe Shiancoe. Carlson, who missed all of 2011 with a shoulder injury, must prove that he still possesses the pass-catching acumen he did while racking up 12 touchdowns in 2008 and 2009 in Seattle. His arrival means the team will roll out plenty of two-tight end sets, and they likely have grand visions of a New England-type offense that features two elite pass-catching tight ends, a dominant slot receiver, and just enough outside receivers to keep a team honest. It's ludicrous to suggest that Ponder, Carlson, Rudolph, and Percy Harvin can even approximate the well-oiled machine run by Tom Brady in New England, but it certainly appears that's the model. If Carlson gets hurt or if offensive coordinator Bill Musgrave proves incapable of using his assets efficiently and effectively, the natives are going to get extremely restless.

QB Christian Ponder – Ponder may be the most obvious name on this list, but he's worth discussing. Even if it turns out the front office nailed every draft pick and every offseason acquisition (and, frankly, even if the other nine names on this list all go boom in 2012), none of it will matter if Ponder can't take significant strides forward in 2012. While he brought some excitement and displayed moments of brilliance in 2011, there were plenty of rookie mistakes and, of course, plenty of nagging injuries. Assuming Ponder stays healthy, Vikings fans need to hope he learned from his mistakes last year, that his grasp of the offense will improve after a full offseason program, and that the efforts to upgrade the offensive talent around him will bear fruit. The Vikings will undoubtedly be happy if Ponder simply shows modest improvement over 2011 and at least limits his mistakes, but will that be enough for an impatient fan base that's been rejuvenated by the new stadium? Will it be Ponder under center when the new stadium opens in 2016? If he treads water or regresses in 2012, will the team have to move on to Plan B already next year? Will Leslie Frazier be around to find out? Will Rick Spielman? Failure to develop a first-round investment in a quarterback can set a franchise back for years. No pressure, though, Christian!