The Mets signed C Ronny Paulino this week to a one-year deal. On the surface, the move makes a lot of sense. I’ve written about how the Mets need a RH-hitting catcher who hits lefties hard to complement Josh Thole, and Paulino seems to fit the bill. Paulino’s stats vs. LH pitchers since 2006:OBPSLGISOBABIPBB%HRPA2006.402.443.104.3788.7%21272007.462.593.185.4198.4%51192008.308.392.147.24110.3%1392009.343.458.168.3247.7%51432010.380.516.158.3834.0%3100In general, these numbers strongly suggest that Paulino can in fact hit right-handed pitching. But, the stats do raise a couple of points for concern. First, Paulino’s best seasons have been fueled by unsustainable BABIP’s. Paulino may be good against lefties, but when success is fueled by that high of a BABIP, we should be concerned. And lest you say that Paulino is just “really good against lefties,” I point you to the fact that Albert Pujols has a career .321 BABIP against southpaws.Plus, there’s also Paulino’s 2008, which shows us both the perils of the small sample size, as well as the variability of BABIP-fueled success. In ’08, Paulino only had 39 PA’s against lefties, in that small sample, his BABIP was only .241. His numbers against southpaws are, as you might imagine, much, much, lower. The difficulty, however, is that it’s hard to ever get enough PA’s against lefties for it not to be a small sample size. This means that if Paulino’s BABIP falls off (and even Albert Pujols had a BABIP “slump” against lefties last year at .248) he’s going to struggle.His struggles will only be amplified if his walk rate continues its precipitous fall. Plainly, walking 4% of the time just doesn’t cut it. To see what’s happened to Paulino’s plate discipline, we can look at his O-swing% (percent of pitches swung at outside the strike zone), Z-swing% (percent of pitches swung at inside the strike zone, and his Zone% (percent of pitches faced inside the strike zone).O-Swing%Z-Swing%Zone%200617.8%75%47.1%200721.5%67%56.2%200821.5%64.7%53.4%200921.9%67.9%50.8%201024.7%65.6%46.9%The above chart confirms what we might have feared—Paulino has started swinging at more pitches outside the strike zone, and in return, pitchers are throwing him fewer pitches inside the strike zone. If this trend continues, and Paulino suffers a drop in his BABIP, his numbers are going to plummet.But, this actually wasn’t why I was concerned when I heard about the signing. What concerns me is that Paulino is currently serving a 50-day suspension for testing positive for an illegal substance. Paulino says he took diet pills that unknowingly contained a banned substance. I have no reason not to take him at his word. Although I will note that if Paulino tested positive for amphetamines -- the illegal substance most likely to be found in weight control pills – certain kinds of amphetamines can be used as a masking agent for steroids.More to the point I wondered, how have mlb position players performed coming off suspensions under the testing policy MLB implemented in 2005? Here, I’m using TAv., OBP, and SLG to evaluate.PlayerMatt Lawton: 2005 (pre-suspension): .273/.380/.433 (.287 TAv) (NL stats only)2006 (post-suspension): .259/.310/.259 (.200 TAv)Neifi Perez: 2006 (pre-suspension): .254/.266/.343 (.205 TAv)2006 (post-suspension): .200/.235/.215 (.150 TAv)Mike Cameron: 2007 (pre-suspension): .242/.328/.431 (.278 TAv)2008 (post-suspension): .243/.331/.477 (.282 TAv)Jose Guillen: 2007 (pre-suspension): .290/.353/.460 (.286 TAv)2008 (post-suspension): .264/.300/.438 (.253 TAv)Jay Gibbons: 2007 (pre-suspension): .230/.272/.348 (.216 TAv)DNP in majors next 2 seasonsEliezer Alfonso: 2007 (pre-suspension): .250/.284/.359 (.208 TAv)2009 (post-suspension): .175/.197/.254 (.117 TAv)Manny Ramirez 2008 (pre-suspension, with LA): .396/.489/.743 (.396 TAv)2009 (pre-suspension): .372/.500/.6542009 (overall, post-suspension): .290/.418/.531 (.327 TAv)Save for Manny not the most illustrious offensive group pre or post suspension. The trajectory, however, save for Mike Cameron is clear: players who test positive for illegal substances tend to have some fall-off in their performance once they return.Clearly, the Mets did not make a significant investment in Paulino, so the risk here is limited. Nonetheless, don’t be surprised if we see Dusty Ryan at Citi Field (who the Mets also signed this week, undoubtedly per my earlier suggestion) as the right-handed part of the catching platoon, before the season is out.