Harang is on the short list of pitchers that have started games that i've attended. The one thing I remember about the game was that even though Cincinnati isn't very far from Chicago, I saw literally two Reds jerseys and that the Cubs lost putting them into a tie for first with the Brewers as both teams were playing not to win the 2007 NL Central and the Brewers were putting the final touches of blowing a 8 1/2 game division lead.
Either way, 2007 was the culmination of the peak of Harang's career as he tied for his career best ERA+ of 124. For the last handful of years he's been a fairly average pitcher until 2013 when he was one of the worst starters in the league (although he had a decent finish with the Mets).
Harang's career is getting close to being finished and a minor-league deal is probably best case scenario. His most similar player through age 35 is fellow free agent Bronson Arroyo. While Arroyo pitched okay in his age 36 season (2013), I would be surprised to see the same out of Harang considering how far his numbers regressed during his time with the Mariners.
Marquis did have a decent stretch where he was at least an average pitcher but even those days have come and gone (last time with an ERA+ above 100 was 2009). The last few years he's been going from job to job. I'd imagine the same to happen this year but even that can only last for so long if he keeps on putting WHIPs in the 1.5 range up. His most similar pitcher through age 34 was Pedro Astacio and he managed to stick around for about three years afterwards despite putting up below average numbers.
Perez has had what one could call an unconventional career path (that makes it easily forgettable that he's still only 32). He's shown incredible promise at times as a starting pitcher to only be more than counter-balanced with issues of finding the strike zone and alienating some of the teams (Mets) that he's been on. After a disastrous 2009-2010 with the Mets his career looked pretty much done. The last couple years, he's been pitching out of the bullpen for Seattle and had a couple decent and drama free seasons.
He may be one of those players more suited to the bullpen than starting. He has shown the ability to still strike out batters (12.6 per 9 innings last year) so i'm sure he could be an asset to someone's bullpen and maybe one day be a designated ninth inning pitcher. His most similar player through age 31 is Pete Schourek who had a 102 ERA+ in 33 games for the 2001 Red Sox before his career came to an end. My guess is that Perez has more than one year (maybe closer to five years) as a reliable arm out of the bullpen.
Andrew Bailey came out very strong out of the gate with dominating seasons in 2009 & 2010. However, the last few years have been marred by injury and ineffectiveness. Bailey could be a good low-risk/high-reward. His most similar player through age 29 (John Axford) has basically gone through the similar trajectory and is coming off an up and down season with the Brewers & Cardinals. Based on his early career promise, Axford managed to get a 1 yr 4.5 million dollar deal. I still think Bailey could manage to get something along the lines of 1 yr and 2-3 million on the open market.
All numbers found on baseball-reference.com