It would be worth losing the pick for a player in his 20s who could be a core player from 2018-2020 and beyond.
But I don't think anyone on that list qualifies.
Yoenis Cespedes NYM - 31, big 2015, but otherwise a 3.2 WAR player his other four seasons.
Neil Walker NYM - 31, averaged 3.2 WAR the last three seasons, 2B, not exactly a position of need
Mark Trumbo Bal - 30, 1B/OF, RH, 47 HRs but only 2.2 WAR due to poor fielding
Edwin Encarnacion Tor, 33, 1B, RH, good hit, poor field
Jose Bautista Tor, 35, really fell off last season
Kenley Jansen LAD, 29, closer, has maintained his velocity, if they were close he'd be worth it
Justin Turner LAD, 32, 3B, RH, weird career, replacement level player until 29, then 13 WAR the last three seasons
Ian Desmond Tex, 31, SS/OF, RH, peaked 26-28, bounceback at age 30, buyer beware. His fielding has regressed, as an OF a 1-2 WAR player.
I don't see anyone on this list I'd give up a late 1st rd to sign to a big contract.
Either they're too old or not a position of need.
Jansen is the best value (in terms of sacrificing a draft pick) but if we're trading RPs for prospects, "trading" a draft for a RP doesn't make sense.
Dexter Fowler ChC
Jose Bautista Tor
Kenley Jansen LAD
Justin Turner LAD
Ian Desmond Tex
Dexter Fowler ChC