Don't look at Canhas slash line, except for the OBP. Look at his production vs league average. He was 15% above average offensively and has position flexibility.
Thats a lot more than incrementally better than what we have had.
Now, who knows what he will get in free agency, but the market for 33 yr old corner OFs is hardly robust. Look around MLB and see how many teams will be in the market for him. Not any of the rebuilders...and probably not the mega bucks teams. And there are several much better and usually much younger OFs that are gonna fill up the market and drive the price down, like Eddie, Castellanos, Soler, Schwarber, Marte, Bryant, Garcia, Conforto, Pederson, and Pollock. Once everybody signs those guys, how many teams will be left? I think its doubtful that he's gonna get a three year contract...maybe two with an option that nobody plans to ever pick up.
We do not have the wherewithal to add two 4 WAR OFs. The idea that we can afford to shop in the Mercedes lot is loony tunes.
The free agent options to Canha are guys like McCutchen (35), Pham (33), and Calhoun (34). We need a productive short term bridge to Valera, and Canha may fit the bill.