When the Eagles signed versatile fullback/tight end James Casey in March, coach Chip Kelly spoke about the increase of two tight-end formations, about the creation of a lethal tight end tag team similar to New England’s Rob Gronkowski and Aaron Hernandez.

Casey and veteran tight end Brent Celek, right now, are Kelly’s vision of the Gronkowski-Hernandez pairing. Backups Clay Harbor and Emil Igwenagu are OK but haven’t proven themselves to be dynamic.

Hoping to emulate the Patriots, who have stockpiled at the position, the Eagles have closely examined this year’s college crop of tight ends, and several league officials familiar with Kelly’s background and offense expect the Eagles to add depth there before the end of the draft.

Are they going tight end at fourth overall? Of course not.

But with at least five tight ends expected to go in the first three rounds, the class is deep enough for the Eagles to come away with one in the later rounds who could make a significant impact in 2013.

The creme of the crop is Notre Dame’s Tyler Eifert, the cleanest and most complete of all the tight end prospects. Some analysts and scouts think Eifert could go as early as 15th. NFL Network draft czar Mike Mayock has Eifert rated as his 13th overall prospect and the only tight end in his top 45.

After Eifert, opinions are mixed (see tight end position preview). Stanford’s Zach Ertz is considered late-first, early-second round material. San Diego State’s Gavin Escobar should go in the second or third rounds. Cincinnati’s Travis Kelce, the younger brother of Eagles center Jason Kelce, has deceivingly good athleticism along with plus blocking acumen. He is a fast-riser, once considered third- or fourth-round eligible but now viewed as a potential early second-rounder.

Rice’s Vance McDonald and Florida’s Jordan Reed could also be gone before the start of the fourth round.

The Eagles held private workouts with Ertz, Escobar and McDonald and brought Kelce into the NovaCare Complex for a pre-draft visit, which shows their level of interest in the position.

“Similar skill set in terms of body type, athletic ability, receiving ability,” Eagles general manager Howie Roseman said when asked to size up the class. “And then you need to make a determination on what you’re looking for from a blocking perspective.

“I think that’s where these guys may start to separate a little bit, depending on what you’re looking for. Everybody has a scheme that looks for different things from those guys, and fitting them in in different places.”