Jair Jurrjens has a career 112 ERA+ in 750 major-league innings. That, by itself, makes Jair Jurrjens seem like a pretty useful pitcher. Like with Brett Myers, though, simply citing career numbers doesn't even begin to describe what you can actually expect from Jurrjens, who has been all over the place in his career. Now that he's signed on with the Baltimore Orioles, bringing him back to the American League but to the AL East for the first time, it becomes important to discern just which version of Jurrjens can be expected to show up in 2013.
Jurrjens was on the disabled list in 2011 three separate times for right knee issues, but, despite those problems, he replicated his previous season's strikeout-to-walk ratio, and managed a sub-three ERA in his 150-plus innings of work. As with his other highly successful campaigns, Jurrjens batting average on balls in play was well below the league average. It wasn't due to luck with line drives, either, as Jurrjens' limited opponents on both fly balls and grounders, the latter of which he induced at a 42 percent rate, the third time in his career in which he had reached at least that level.
The 2012 season did not go nearly as well. While some regression was expected, especially since he's already experienced the highs and lows of BABIP in his career before, this went far beyond that, with Jurrjens compiling a 6.89 ERA in the majors in 10 starts, while also pitching poorly in 72 innings and 14 starts for the Braves' Triple-A club. Jurrjens lost a rotation spot, then lost a roster spot this off-season, leading him to sign with the O's, who, after a 2012 season in which they had 12 different pitchers start, aren't about to say no to any potential rotation insurance.
Jurrjens induced fewer grounders last season, but the ones that did exist found far more holes, with opponents putting together an OPS+ nearly 60 percent better than average against him on that batted-ball type. His velocity fell once more, but despite this, he threw a larger percentage of fastballs. His four-seamer, so useful in 2011 according to PITCHf/x pitch values, was well below-average in 2012, and none of his secondary stuff could make up for this. Given more of his pitches outside of the zone induced contact, and the results were not in his favor, one can presume that he was having more trouble hitting his spots, and hitters made him pay for it. The fact he struck out just 3.5 batters per nine also makes this likely.
The most significant red flag for Jurrjens yet to be mentioned is the change in parks. Orioles Park at Camden Yards is a hitter's park, and one that significantly boosts both the home run power and overall run scoring of left-handed batters according to Stat Corner. That's the opposite of the situation in Atlanta, where run scoring is slightly depressed for left-handed batters, and homers come at a neutral pace. This is significant with Jurrjens, as he has allowed lefties to hit .275/.350/.431 against him in his career despite his home terrain.
Combine that with the existence of the designated hitter in the AL rather than a pitcher, it's even more imperative that Jurrjens is able to hit his spots once more. He doesn't have swing-and-miss stuff, so his whole game is about inducing weak contact and getting enough grounders to survive. Throw in that he has exceeded 200 innings exactly once in his career, and you can see where there are plenty of risk to having Jurrjens around from both quality and quantity standpoints.
That thought process also applies in fantasy, where Jurrjens might take up a roster spot better given to someone else. The thing is, though, in a deep AL-only format, there is enough upside here that he's worth paying attention to, possibly grabbing late for either $1 or as one of the free-of-charge bench options, should your league partake in such things. Just be aware that, should Jurrjens actually get a chance to start in Baltimore, there's a very real chance you'll regret every moment of your time with him.