Clay Mortensen (1-0, 2.01) has been decent enough in his first year with the Rockies. In 22.1 innings, he has the very good ERA, a 4.43 FIP and a 4.19 xFIP. Over his career in the majors, Mortensen has pitched a grand total of 59 innings and has a 5.19 ERA and a 5.38 FIP. Over his career, he has a 4.73 K/9 and a 3.66 BB/9, both of which are in line with his 2011 numbers. For the rest of the year, ZIPS has his projected numbers for the Rockies at 18 more starts, a 6.53 ERA and a 5.52 FIP. Hopefully those are closer to the numbers Mortensen ends up having tonight.
According to Texas Leaguers, Mortensen throws a mid to high 80s two seamer, a low 80s slider, and a low 80s changeup, so not exactly the best "stuff". Of course, this year fangraphs has each of his pitches at above average value. Mortensen has only faced two current Brewers; both Carlos Gomez and Yuni Betancourt have two PA against him. For what it's worth, in those appearances, Yuni has a 2.000 OPS and Gomez has a 1.000 OPS.
Shaun Marcum (5-1, 2.54) has been the best pitcher on the Brewers in 2011, compiling a 1.6 fWAR already (tied for the 8th highest among NL pitchers). Marcum also has a 2.61 FIP, also 8th in the NL. This year, he has a 8.58 K/9 and a 2.06 BB/9. Also, Marcum's changeup is really, really good.
Three different Rockies hitters have faced Marcum at least ten times. Here is how they have fared:
And in the bullpen:
Kameron Loe pitched .2 innings (12 pitches) Thursday and 2 innings (22 pitches) yesterday.
John Axford pitched 1 inning (13 pitches) yesterday.
LaTroy Hawkins pitched 2 innings (15 pitches) yesterday.
Mike McClendon pitched 1 inning (28 pitches) yesterday.
Marco Estrada pitched .2 inning (16 pitches) thursday, and also pitched on Wednesday