If Flacco can increase his accuracy slighlty and be a 60-63% passer this season than you will notice Boldin having a good value year.
Boldin last year caught 53% of his 106 targets. He averaged 7 targets a game. Had he played all 16 games he would have had 112 targets. Let's say in this up tempo offense that Baltimore is planning on running this season that Boldin's targets go up even .5 per game he would have 120 targets on the year.
He does not offer the big play ability that these other Wr's offer but just to asses those numbers in relation to other WR's: Cruz had 131 targets, Jordy Nelson 96, Steve Smith 129, Percy Harvin 120, Colston 107.
Let's say Flacco is able to have a good year and up his completion percentage from the 57% last year to let's say 62% this year (not out of the question as 2 years ago Flacco was a 63% passer).
Let's assume that Boldin does get 120 targets this up coming year. If Flacco has a bounce back completion percentage year, I can see Boldin catching 75 of those 120 targets (63% of his targets). As a possesion guy that is definitley a doable stat. When he played with Warner in Arizona he had years where he would catch 70% of his passes. Now Flacco is not Warner and Boldin is not the same player but it is an attainable number.
Boldin had a ypc of 15.5 yards last year. I don't think his YPC will stay that high but if he caught 75 balls and had a ypc of 14.5 he would still have 1087 yards on the season. Td's are not easy to predict, but let's give him 6-8 tds on the year.
Boldin can be had for pretty cheap and a year like 75 catches, 1100 yards, with 6-8 td's are nice numbers for a WR3. Especially if you decide to address other positions first in your draft. Boldin is an unsexy pick as his upside at this stage is limited but he can offer some value.