The Diamondbacks signed IF/OF Willie Bloomquist to a one year, $1M contract for 2011, with a mutual option for 2012. What does Bloomquist add to the team, and whose roster spot will he take? 

There are two positive attributes that Bloomquist adds to the Diamondbacks - versatility and speed. Bloomquist played 8 different positions in 2010, everywhere except pitcher and catcher, even getting in one game as a DH. With teams moving to 11 or 12 man pitching staffs, a player who can play any position does have some value. The second aspect that Bloomquist adds is speed. For his career, he has stolen 104 bases in 127 attempts, good for a 82% success rate, which means he does add a base-stealing threat to the bench. Of course, he will be 33 this year, so even that skill is probably diminishing.

But aside from those two positives, there are quite a few negatives. Bloomquist has a career .317 OBP, which is below average, and a career .336 SLG, which is way below average. At least he does have better numbers in clutch situations, batting .262/.359/.346 (705 OPS) for his career with Runners in Scoring Position, and .283/.329/.377 (705 OPS) in Late and Close Situations, compared to a 653 OPS overall. Defensively, he's not considered to be a particularly good defender anywhere, but is probably adequate as a backup SS or 2B. 

With Bloomquist guaranteed a roster spot in 2011, whose roster spot is in trouble?  The following players should be set:
C: Miguel Montero, Henry Blanco
1B Juan Miranda (out of options)
2B Kelly Johnson, Willie Bloomquist
SS Stephen Drew
3B Melvin Mora, Geoff Blum
OF Justin Upton, Chris Young, Xavier Nady

That's 11 roster spots locked up, leaving only 2 or 3 spots for a group including Brandon Allen, Gerardo Parra, Tony Abreu, Ryan Roberts, Wily Mo Pena, and Cole Gillespie.  Clearly, it depends on what happens in spring training, but I would like to see Brandon Allen become at least a platoon starter in LF. I think Parra has a leg up on the next slot, since he can serve as a quality defensive backup for Allen/Nady in LF, and also for Young in CF. The player whose job is in trouble is probably Tony Abreu.  After some promising seasons in AAA, Abreu had a very poor .233/.244/.316 line in 2010, with a terrible 47/4 strikeout-to-walk ratio.  He's not regarded as an exceptional defender, like an Augie Ojeda, so he really needs to hit to be useful. I think Abreu will have to go back to AAA to find his batting stroke again, and Bloomquist will serve as the backup SS, along with Geoff Blum.