Walker went 1-for-4 with a solo home run in Tuesday's 8-5 win over the Padres.
Walker launched his third home run, and all three have come against right-handers even though Walker has started exclusively against lefties to this point. Manager Torey Lovullo says first base is not a platoon, but it looks like one. The manager is also having Jake Lamb take fielding practice at third base, so something's brewing on the right side of Arizona's infield.