This signing was a result of a desperate and immeadeate need for a catcher by the M's. This will slow clement's progression through the system but overall will be best for him in the long run. His bat is already ahead of his peers but from what i hear, as with most good hitting catchers i.e. Neil Walker, Salty their d- is not up to par. So his development will be better in the long run because he'll have more time to develop a better all around game rather than being rushed and having problems. I dont know the length of jojima's contract but my guess is that this was done to sure up the position until clement is pretty much garunteed to succeed when he is called up. I think the M's are scared off of rushing catchers after the Olivo fiasco, (he could have used more time in the minors) so they did what they do best and signed a top japanese player. I also belive this move is done to help bolster fan support which has waned over the past two losing seasons, which is evidenced by ichiro's comments. So to put it bluntly; yes it will slow clements rise to the majors, but no it will not hurt him. He'll have all the time to work out the kinks and when he's ready the job will be his.