I've gone through the batters on my fantasy baseball roster, i'm going to go through position by position on players that are available and owned in between 10% to 49% of Yahoo leagues as of the writing of this post.
Russell Martin (19% ownership)
While his value has regressed in comparison to earlier years in his career, he can still provide some power from a position that sorely lacks it (18, 21 & 15) the last few years and he'll even throw in some stolen bases.
The risks/downsides are that defensive metrics are not counted in fantasy (his dWAR of 2.5 was his best total since 2007) and he's a liability when it comes to batting average (.237, .211, .226) the last few years. His defense was good enough that he still managed a 4.3 WAR despite putting up average offensive production (100 OPS+).
Quite frankly, he's more valuable to a real baseball team than a fantasy baseball team. His most similar player through age 30 is Benito Santiago. In his age 31 season he put up a .264/.332/.503 118 OPS+ and 30 home runs. I wouldn't put too much stock in Martin hitting 30 HRs out of nowhere as this season occurred in 1996 when 30 home run seasons seemed to be falling out of the sky.
Ryan Doumit (15% ownership)
In the past Doumit has provided some value with a little bit of power and occasionally has helped in the batting average category as well.
Even though the power numbers held up okay playing at Target Field, it appears likely that the playing time is going to be less than prior years. While he is catcher eligible this year, this could be going away in the near future as it seems like he'll be spending most of his playing time in the outfield which would further reduce his value going forward.
Through age 32, his most similar player is Eddie Bressoud. During his age 33 season, he saw a reduction in playing time and only had a .648 OPS. I'm not sure Doumit's offensive production is going to see that sharp of a drop off (I think OPS ends up in the .700-.725 range) but wouldn't be surprised to see him only get about 300-400 plate appearances this year.
Carlos Ruiz (12% ownership)
Ruiz had a nice three year stretch from 2010-2012 where he helped in the batting average category and even helped with power slugging 16 home runs in 2012.
On the downside, his performance regressed pretty hard coming in with a .688 OPS and the one category where he was somewhat strong in batting average (.268) took a step back at an age (34) where several players see the beginning of the end.
His most similar player through age 34 is Ron Hassey. In his age 35 season, he posted a .257/.323/.368 7 HRs in 365 plate appearances. For 2014, Ruiz shouldn't be in danger of losing playing time as the Phillies don't have many viable options at catcher but don't expect him to rebound to his 2010-2012 form and it seems inevitable that he'd miss time with an injury at some point.
Travis d'Arnaud (10% ownership)
Unlike the other three catchers, d'Arnaud is largely an unknown entity when it comes to how his career will turn out.
In 31 games last year, he didn't set the world on fire .202/.286/.263 58 OPS+ but at least he showed a good eye drawing 12 walks in 112 plate appearances.
Despite this slow start, there are several people that are high on d'Arnaud. He's been on several top 100 prospect lists and he's crushed minor league pitching (OPS above .900 in the last three years). Point being, he's going to get his opportunity to prove his worth as he's done all that he can against minor league pitching.
The only question is whether he will be a legitimate contributor or if he's a 4A prospect. I think he's at least worth a late-round flyer if your filling out your bench but I think best case scenario is about 1-2 years before he'd be a top flight fantasy option at catcher.