HAL PH J Holt for Joe Morgan?

Only Gm 6 of the season and HAL PH J Holt (LHB) for Joe vs a M Caldwell (LHP) with 2 out no runners on base?
Does this indicate Joe is in his '76 (5R) yr.?
Does it mean Holt is in his '73 yr? (best yr vs. LHP)
After 6 gms.:
Holt is 5-5!
Morgan is hitting .471 vs. RHP and .143 vs. LHP.
Is it coincidence or a true read?

It means Holt has a better card against LHP than Morgan. Pinchhitting a L for L is a major clue.