On 29 April 2009, the Nationals traded a minor league roster-filler pitcher, Kyle Gunderson, 48th-round pick in 2007, to the Florida Marlins for Logan Kensing, a hard-throwing right-handed relief pitcher who had worn out his welcome in Miami through not pitching particularly well after Tommy John surgery. Manny Acta threw Kensing into the fray at his first opportunity on 30 April, and the 26-year-old has made five more appearances, most recently on 11 May.
Date Inning P Situation Net Value
30 April 7 .615 1st, 1 out, up 1 -.123
1 May 6 .099 1st, 2 out, down 5 +.014
6 May 6 .061 load, 1 out, down 3 -.069
9 May 7 .204 load, 2 out, down 1 +.164
10 May 6 .592 none, 0 out, up 1 -.564
11 May 5 .069 load, 2 out, down 5 -.014
He's responsible for losing over half a game in the short span of about two weeks, as his Value scores add up to -.592 (A value of 1.000 would equate to a game.)
But looking more closely at the data, Kensing is a tolerable mop-up man when behind. The disappointment is that he has absolutely failed to protect a lead. You wonder whether he gets too nervous when it's close. I think he might stick in the Nationals' bullpen, if they've still got players there with options, as the sixth man coming out to fill-in during blowouts.
EDIT: Kensing was designated for assignment the same day that I wrote this. I also corrected some mistakes in my calculations above.