I think it would be really easy to make a Kirk/Valenzuela tandem work, at least in the first few weeks after Kirk returns. I think the club is going to carefully monitor Kirk's playing time in the beginning and for the first while they could run more of a 1A/1B tandem like back when Jansen was still around. I think Valenzuela has been showing glimpses of being an impact level of player given how elite the overall defensive package is behind the plate, and keeping Heineman in place of Valenzuela would be a massive downgrade to the club even with Kirk's return.