Buy or Sell: J.D. Martinez, Nova, Bay

J.D. Martinez is filling in nicely for the departed Hunter Pence. Ivan Nova has two wins and a 16/1 K/BB ratio since returning from triple-A, allowing only three earned runs in the process. Jason Bay has three home runs in his last seven games and a history of hitting the long-ball. Are these players going to help your fantasy team the rest of the way?

J.D. Martinez, OF, HOU
When Hunter Pence was traded away to the Phillies, J.D. Martinez finally got his shot to play everyday in the big leagues. It seems that his transition from hitting .338/.414/.546 at double-A has gone “smooth as silk”. In his first 10 games, Martinez has put up a .306/.359/.722 slash line with four home runs. Given his minor league track record — he’s a career .342/.407/.551 hitter over 1261 plate appearances — the fact that he’s hitting for AVG is no surprise. However, at no point in his minor league career did he show signs of becoming a big-time power hitter. Martinez has four home runs in his first 36 at-bats, which is a pace that no one can maintain (9 AB/HR). He’s also slugging over .720, which will not hold.

Given his line-drive approach and ability to hit for AVG at every level he has crossed, Martinez is certainly a player that you take a chance on and hope the maybe he pops out a few more homers. In the end, however, we’re probably looking at more of an AVG-only player here, especially with the limited runs and RBI opportunities of hitting in depleted Astros lineup. Ride the hot streak, but have backup options in mind.

Eyeball ROS projection: .290/.338/.430 with 4 HR

Ivan Nova, SP, NYY
There was a point last season where Nova generated mixed league buzz, as he posted a 2.45 ERA and 1.18 WHIP in August. That production didn’t last long. Nova posted an ERA over five in September and finished the season with a 4.50 ERA, 4.35 xFIP and a well below average 1.5 K/BB rate in 42 innings with the Yankees. Nova’s recent streak has him back on the fantasy map, but will he fade the same way he did last August?

With 106.1 innings pitched for the Yankees this season as of Wednesday afternoon, Nova stands with a respectable 3.81 ERA and 4.03 xFIP. However, his K/BB rate of 1.8 is still below league average. What has helped him is his ability to keep the ball on the ground more often than not (54 percent ground-ball rate), but his inability to miss bats or limit walks makes him a risky bet going forward.

The Yankees are currently running with a six-man rotation, but manager Joe Girardi wants to go back to a five-man rotation eventually. This means that there is certainly a scenario in which Nova is back at triple-A or pitching out of the bullpen.

As a free agent add in mixed leagues, Nova is worth taking a flier on, especially with a schedule that should line him up to pitch against the Royals, Twins and Orioles the next three times out. If he continues to pitch well over those three starts — and his start today against the Angels — he’d be a prime candidate to sell if your trade deadline is later than most.

Eyeball ROS projection: 4.06 ERA, 1.42 WHIP, 4 W, 22 K

Jason Bay, OF, NYM
It has been a tough couple of years for Jason Bay, who hit 36 home runs with the Red Sox in 2009 before signing with the Mets that following offseason. Until his 2010 season, in which his power numbers declined and a concussion kept him on the DL for a large chunk of the year, Bay had hit at least 30 home runs, scored 100-plus runs and had 100-plus RBI in four of his previous five seasons. Some have come to question whether his relevance in mixed league fantasy baseball is done.

In his last few games, Bay has shown us shades of the player he used to be. Since the calendar turned it’s page to August, Bay has hit three home runs and raised his AVG from .234 to .251 and his SLG from .342 to .370. Small steps, but steps in the right direction nonetheless.

It’s quite understandable that Bay got off to a slow start this season. He missed 67 games last season due to a concussion, which is an injury that can have lingering effects for quite some time (see: Morneau, Justin). Bay has also missed a few games this season due to nagging injuries. If he’s finally 100-percent healthy, I think we could continue to see an upward progression in his numbers going forward. To this point in 2011, Bay has already belted three more home runs than he did last season and has done so in 29 fewer at-bats. Also improved this season is his contract rate, which was 74 percent in 2010, but has bounced back to 79 percent so far this season. That should be a key factor going forward for both his power and AVG/OBP production.

While expecting a huge final couple of months seems more like wishful thinking, there are reasons to believe that the best part of Bay’s season is yet to come. Feel free to take a chance on the 32-year-old Bay, who’s track record suggests that he is capable of so much more.

Eyeball ROS projection: .266/.345/.430 with 6 HR and 4 SB