Walker won't find his name mentioned with the elite at the second base position, but he's a solid option at the keystone. He brings a well-rounded 5×5 line to the table, though he's not an efficient base-stealer and shouldn't be counted on to steal more than a handful of bags.
Walker does a good job of barreling balls and ripping line drives, which should allow him to hit around his career batting average of .280 this year. His power is trending upwards, which makes sense given that he's entering his peak power years. If he's able to stay healthy and receive over 600 plate appearances, I expect Walker to reach the upper teens in home runs.
Walker battled lower back issues last year and missed 25 games as a result, so staying healthy isn't a given. That said, he is now fully recovered from the herniated disc in his lower back that ended his season, and he'll be ready to go in the spring. He should be a fringe top-10 second baseman this year, and he's a good choice for owners that don't want to spend a high draft pick or a significant chunk of their auction dollars at the position.
Ramirez finished last season as the 132nd most valuable player according to our Player Forecast Manager. He stole a career-best 20 bases, and they came on a career-best success rate. It's possible he carries over some of his gains in the category to this season.
Unfortunately, there is little else to like about Ramirez's 2012 season. He finished the year with career-low single-season totals in runs scored, home runs, and batting average. His already low walk rate collapsed to an embarrassingly low 2.6 percent. He was amongst the league's freest of swingers, ranking sixth in swing percentage at pitches outside the strike zone among hitters that saw over 1,000 pitches. Ramirez is able to make contact at a high rate, which is why his strikeout rate remains low in spite of his propensity for chasing, but as last year illustrates, not all contact is good contact.
One down year at the plate isn't reason enough to pull Ramirez off draft boards. Assuming his chase rate returns closer to previous levels, he should regain some of his power and batting average by hitting pitches he can better handle. It's easy to lose sight of the value of staying healthy, and that's one of the greatest traits Ramirez possesses. Ramirez has played in over 155 games each of the past three seasons and hasn't played in fewer than 140 since his rookie season in 2008.
Castro catches a lot of flak from the advanced stats community, but he's a very good young shortstop and offers a bit of everything in fantasy. Castro was the 41st most valuable fantasy player last year, and as a 22 year old (he'll enter this season 23 years of age), that's still honing his craft at the highest level, so it's not unreasonable to expect further growth.
He wasn't the most efficient base stealer last year (66 percent success rate), but his 25 stolen bases were a new single-season best. It was also his second season stealing more than 20 bases. His power is on the upswing, and as he continues to physically mature, that should continue. Castro's groundball rate has dropped a bit each season, and his home run power would be further aided by that trend continuing. Castro hit .300 or better his first two years in the majors, but that average dropped to .283 last year. He needed a BABIP better than .340 to reach the .300 batting average plateau in his rookie and sophomore campaigns, so it may be a bit optimistic expecting a full bounce back in average without further skills growth.
Like Ramirez, Castro is a safe bet to stay on the field. He played in 158 games in 2011, and he played in all 162 games last year. As an integral part of the Cubs lineup he'll continue to hit in prime run-producing spots in the order. Castro isn't quite keeper league gold, but he's close. He's a young player at a premium position that should be in the mix to finish in the top five at shortstop annually for as long as he remains at the position.
Contrary to his “Yes” designation in Deep keeper leagues, I don't expect Profar to finish in the top 100 in player value this year. That status was given with the thinking being that he could be kept indefinitely. If that's not the case in your league, and the window to keep players is short (say three years or less), adjust accordingly. The Rangers have found themselves in the rumor mill this offseason, but they've yet to make a big deal. Part of the reason they haven't made a trade could be a reluctance to include Profar or incumbent shortstop Elvis Andrus in trades. With free agent dominoes falling, things could change.
As it stands, Profar could find himself on the outside looking in when the team breaks camp. It's also possible, however, that the team could move Ian Kinsler off of second base (possibly to first base), thus eliminating the need for a trade to open up playing time for Profar. Regardless of how the rest of the offseason plays out, Profar is arguably the top prospect in baseball. Not only was he was the youngest player to play in the majors last year, he was also the youngest player to play at the Double-A level.
Shortstop stinks in fantasy, and that makes it worth gambling on a player of Profar's prospect stature, even if the immediate payoff isn't great. Jason Parks wrote a glowing review of Profar back in August, saying he “should develop into a perennial .300-plus hitter at the major-league level.” Profar profiles to bring more than batting average to the fantasy landscape, as Jason wrote in the linked review, making him a potential fantasy star.