I really haven't followed him since he got traded to the Cards but has Jason Heyward shown anything other than "potential" and "promise" in his career? I just looked and he's got 9 HR and 40 RBI this season, kind of stinky but his average is better than most of our guys so I guess there's that but it seems he's been rather underwhelming IMO
Heyward is still developing as a hitter. He's only 26. He also hits for average, gets on base, and steals bases. Let's not forget, he plays probably Top 10 outfield defense and has an arm that rivals most. Even in CF, he's above average to good. Frankly, I think we play Harper in CF and play Heyward in RF. When Werth goes down, Taylor in CF and Harper in LF.
Second, because he's still developing, we can expect his power to increase somewhat. I don't think he'll ever match 2012 where he crushed 27 homers, but I could see him getting to the 20 mark. 20/20 doesn't exactly grow on trees.
4 years/70 million would be a good deal. Maybe three years with a mutual option on the 4th year. He'd only be 30 and still eligible for a big deal.