It will be interesting to see how they balance snaps. I would assume McCarthy will want to have three receivers on the field on almost every down because of the quality there. (You don't take Lamb off the field for a second tight end or fullback.) So Jarwin's playing time will likely depend on how much we use the fullback or even a two-backfield look with Elliott and Pollard, with Pollard or even Elliott able to split out wide to essentially give us a four-receiver look.
It's even possible that Blake Bell could end up cutting into his snaps if we want to put in more of a blocking tight end with our three-receiver set. I can't envision us using two-tight end sets except in short yardage.
They'll want to avoid playing the top WRs for 100% of the snaps. Both Gallup and Cooper have had injury issues.
In 2018 for the 2nd half (after Swaim went to IR) they generally played Jarwin on passing downs and Schultz on running downs.
Back then Jarwin's blocking was well below average. In 2019 Jarwin's blocking was better but I doubt that it will ever be a plus attribute for him.
In 2019 the Cowboys running game was at times negatively impacted by the fact that Witten and Jarwin played almost all of the snaps at TE.
Witten's blocking had declined significantly from his peak.
Normally the 2nd TE is a blocking TE but with Witten and Jarwin neither fit that role.
Even at his peak, Witten was a good blocker relative to other starting TEs but not relative to most dedicated blocking TEs.
I think that "packages" will be a focus for Kellen Moore where he tries to utilize the unique abilities of some non-starter type players. That is most likely Pollard.
KM ran some plays last season with both Pollard and Zeke on the field together. Pollard has the gadget play type ability but also has legit RB and WR abilities.
Also, in training camp KM really worked on the wheel route that turned into a go route by FB Olawale. Olawale has 4.5 speed and is a good match-up in the passing game vs LBs.